I wonder if anyone out there has used the Micro-Detailer? It is an excellent drilling tool, speed variable with pressure on the button, really the only mini-drill you will ever need (for plastic, anyway)--perfect for nearly everything, and Michigan Toy Soldiers also sells the bits for it--both burrs and drill bits. It was originally produced and sold by the now-defunct WWIIModelmaker website, and is great for delicate work--the RPMs aren't sufficient to melt plastic, and it is lightweight, cordless, and so easy to handle. At $24, the price isn't bad, either. Excellent for fine detail, sculpting, carving, drilling portholes, etc. I highly recommend it. My Dremel tool has been collecting dust since I picked up one of these.

http://www.michtoy.com/MTSCnewSite/supplies_folder/cutting_drilling/md1001_micro.html

I'm sure it's available from other distributors--this one just had the best description. It is one of my favorite tools.