I do play solos but I usually incorperate them into the middle of a song.  Also I will have to say that my brain stays 3 to 4 moves ahead of my self like doing martial arts. I do believe that it is all about being creative but I create in my head, then play it.
                                Nutty

I was watching Steve Smith video at Vic Firth a couple of weeks ago. There were portions of the solo that struggled to keep my attention. Lots of tom and double bass flurries. Good chops, seen it before.

Then he goes into a section where he's playing sixteenth notes on the snare, starting with straight sixteenths and moving to an ostinato, while improvising musically with his right hand around the toms and interacting with the bass drum and hi-hat. I'm sure my description sounds like it was bombastic, but it was incredibly beautiful to hear. {Check out Clip #2}

I find myself trying to find different ways to solo -- different tempos, different meters, different interpretations of meter -- whenever I'm learning something new. As you say, I want my brain wrapped around the application. Outside of a clinic, though, I don't think the drum solo communicates to the modern audience. An entire corps of Cuban or Brazilian drummers will have it's declining rate of return for an American audience.

The difference in this ostinato is it was played entirely with his left hand on the snare (snares off) which I thought was unusual.

Hey bongo,

I'll jump in and say that I hardly ever do them in a live setting or at practice.  The music I'm into simply doesn't require any, so I stay away from them.  My limited practice time is mostly spent working on grooves at many tempos, developing a consistent sound, experimenting with different drum sounds, and incorporating short, simple fills to announce/lead my band into a new section. 

Here's a good story of me doing a solo to HELP a gig... 

A few shows back, my guitarist broke a string.  He has his backup 99% of the time so this usually isn't an issue.  But alas, he had forgotten the backup on that night.  One of my inebriated friends in the audience yelled out, "Hey Ryan!  How about a drum solo?!"  I looked around, got the audience and band approval, and proceeded to play a 5 minute solo while the guitarists changed out the broken string.  I just stuck with a theme.  Played a groove, moved the individual parts to different instruments (hi hat to floor tom, etc...), included some fills that I knew the people would enjoy (Elvin & Bonzo style triplets, etc...), and then completed the solo.  From what I could tell, the crowd liked it and it saved face for the guitar player. 

As far as watching extended solos, I do find that I sometimes get bored.  I can watch or listen to Lang, Minnemann, Grant Collins, and others like that for a while, but then my mind inevitably wanders.  However, I could listen to Phil Rudd play "Back In Black" or Charlie Watts play "Beast Of Burden" THOUSANDS of times.  Drummers like Lang and Minnemann are so advanced technically that I have a hard time even comprehending/decoding what they're playing, even when slowed down.

Overall, I agree with every statement you made with your OP.  My favorite extended drum solo is Joe Morello's "Shortnin' Bread" from the "Gone With The Wind" Dave Brubeck record.  The drums sound wonderful, Morello is on fire and very musical, and there are a couple of stray rim hits to give us mortals hope!   

Well, I hope this was some form of positive contribution to the thread.   

In the small jazz groups I play with my solos tend to be either 4-8 bars or are full choruses.  In either case, I maintain the form as much as possible.  I occasionally get an open solo, and it will be completely improvised.  Again, I try to keep the feel of the song.

In my rock band I do an open solo every night on the Allman Bros. tune "Hot 'Lanta."  Length and content depend on how I feel that night and what's in my head, although I have a couple of things that I do (almost) every time.

My big band leader is not a fan of long drum solos, but did write a chart on "Little Drummer Boy" for our Xmas cd that has an open solo for me, and we did it last weekend at a Xmas concert.  As usual, I wasn't sure what I'd do till I did it.  Must have worked out ok, though.  He said somebody came to the cd table and when asked which disc he wanted answered, "The one with the most drum solos."

As a drummer I kind of shy away from extended solo because I think it really takes a lot of time to put together a decent one that won't lose the audience's attention. It is a lot more than just going up there and blowing a lot of licks. I lean more toward the in song type of solos such as "AJA" and things like that.

A few weeks ago my guitar player, buddy, asked me to go the the local Guitar Center with him on 14th St. so he could look at some acoustic models.

When we entered the store we discovered that they were having the regional drum offs there, and they were due to start within 15 minutes so we stuck around. I'm not sure where all of the contestants were from but I saw guys from Maryland, Ohio, New York and Boston. Sean Pelton and two other NY drummers were the judges.

I was surprised that each player had 5 minutes of time. 5 minutes is a LOT of time to fill if you don't have a lot to say.

Most of these guys had really good chops, and a few had some left foot clave exercises down, but mostly they were just playing a series of licks, some of the licks were pretty complicated, but as far as being able to construct a  musical solo, they all were pretty dismal. They would mostly play a lick, then play another lick, overall most of them lacked cohesion. (for example: Playing a latin pattern for a few bars then stopping abruptly to do some rudiment work with little transition--it sounded like the needle skipped) That was my drummer's view, my friend's non-drummer, but equally important audience member/musician view was that, "most of these guys are good, but they have said all they are going to say at about 3 minutes, beyond that it just gets boring." I had to agree. (they didn't need to take all 5 minutes, the rules stated they could stop whenever they wanted).

The place was really packed, I'm assuming 90% of them were drummers, but in watching their reactions, they too started to lose some enthusiasm around the 3 minute mark. In watching the judges, I didn't really see them get too excited and high 5 each other over anyone's solo.

So in the right context I like extended solos if done well. You can shoot me for saying this, but I don't like Moby Dick, but I like Buddy Rich's West Sdie Story solos (various versions).