look around
http://www3.towerhobbies.com/cgi-bin...3p?&C=PKJ&P=ML
You can find some deals on used Ham radio Power suppiles. I have an old 60amp beast in my shop. It must weight at least 40 pounds! But of coure they are not all the big. You could even use an old computer power supply. Those go on ebay for 40-50.00 and most put out 20amps.