my thoughts is yo could just make a wood box for your amp (pretty much like a rack case), put some foam around the amp to protect it (but it could overheat so i dont know) and just cover it with some kind of vinyl so it looks pretty
but thats just a pretty rough idea, i dont know of a web site with plans for it
you should ask frederic, the DIY guy here n_n
maybe he hasnt done it before but has some cool ideas