I've only been mapping for the Source engine right now. I havne't tried creating meshes for the engine yet. Source *should* support up to 99 UV channels. We're using the Gamebryo engine to develop our current title (PC,console), and it supports up to 99 UV channels. Source of course, is far more advanced.
This opensource project already has over 200 weapons; so there is value in adding more map formats that it can load. When we programmed in wolfenstine:enemyterritory support into the engine; and then supporting code in the game code; that opened up 600 maps to this project. The same would be nice for unreal 97/ unreal…