Ok, so here is the deal.  You can get a 61 key keyboard for cheap.  There has to be a way space out the triggers underneath the keys and use pads(to lessen the force of the mallet) instead of plastic keys.  That would give you the equvalent of a 5 octave marimba.  The only units available at this time run upwards of 2000 dollars.  So if anyone has any ideas on fabrication or constructive criticism post them.   

This has run through my head a number of times.  The main problem is that cheapo keyboards use printed circuits only.  To space them out, you would have to hand make 61 connections.  I can't see any way other than to buy 36-40 individual triggers.

If any one has any ideas on this, I would also love to hear about it.

Roger