I thought I'd share my small collection of brushless controllers for the family.
From left to right, listed as what kit or who it came from:
1) Pegasus Power Systems 36v 22a??? I'm not sure on the exact current, but I can only guess its a 22A
2) E-crazyman 24v/18A
3) Lyen 24-72v/30A
4) Amped bikes aka 9C 36v/22A
5) Cyclone 36-48v/35A
I haven't worked my way up to big power yet, so I've just been dealing with these average controllers. My 900w cyclone kit is awesome, but as you can see the controller is at least 50% larger than the other controllers (unfortunately in the wrong direction) and its 100% heavier than any of the other controllers shown. The motor might only weigh around 8 lbs, but when you factor in a their freewheeling 3chainring crankset and controller, I woudn't be surprised if it all adds up 15 lbs.
It came with my Pegasus Power Systems 36v/22a hub motor kit. It is physically the same size as the e-crazyman 24v/18a controller next to it, except the mounting tabs were bent back to fit into the battery case that came with the kit.
I think most of the controllers out there are using the same generic cases (dimensional-wise). I read that E-crazyman is willing to try to match your specs if you contact him. Maybe Lyen could put something together for you too. My Lyen controller appears to be put together very well, and I consider it the best of the bunch.