If you have a bunch of amc7135's laying around, you could rig up parallel banks of 3 to 4 in series. The number of banks would depend on how much juice you want to feed.
A easier to construct CC regulator would use the LM1084IT-ADJ. It's like a 7135, but bigger and has no internal voltage sense resistor. That is all you need to build it, 2 components. Here is an Instructable on it. Here's a few posts I have on it. I talk about 3 emitters, but 4 would be better (less voltage differential between supply and demand).