While surfing the internet I ran across this "new invention" by Roland.
http://www.rolandus.com/products/productdetails.aspx?ObjectId=964
When I first saw it, I thought "hey that's kinda cool". I mean they'd be really light to march with, and you could easily control volumes for indoor performances...

but as I started to read the specs, the thought crossed my mind- but wait, you'd need an very large and incredibly precise sound system to reproduce the volume of a real drumline out on the field, and allow the band and audience to hear it. and then the image of a snareline with very long cables tangled around their legs all piled up on the marching field came to mind to give me a laugh... and on top of that, DCI doesn't even allow the use electronic instruments...
so, I guess these would be great for practice though, with the benefits of quieter practice/ rehearsals for less hearing loss, and the rhythmcoach functions, but I want to go to a school that can afford enough of these for their snare line exclusively for practice...

anyway, what do you guys think of these?

Looks interesting, I'll have to check them out at the Texas Bandmasters Convention in July.

Like you, I can invision some technical difficulties with using it outdoors. There are several wireless systems that people are using for miking soloists these days. Invariably, though, when I see a marching band use electronic stuff on the field, there is some glitch that takes them precious set-up minutes to fix.

Interesting concept.  Can't see it working though for the same reasons as above.  Also, I doubt the heads will be able to feel the same as the highly tensioned kevlar heads marching drummers use today.  I'll just stick with my pad and a metronome for practice purposes. 

It looks like it has a wireless sound system built into the module. I would see this more used for indoor winter drumlines. Or maybe for quiet practice outside the band room. When I was on the line my director used to send us all the way to the auditorium for sectionals. This could make it easier to practice like in the next room. A bit pricey though I'd imagine.