I agree with most of your statements. David is also right. The engine is cheap. But Toast brought it to a good point. In this case we dont need expensive new tools. We just need the access to another uv-set. You can surely do it with Lite-C and DirectX. But we only need to attach a second UV-set in MED with texture.

This is not a task to let engine price explode It is a change int the MDL format. I once asked for that in the future forum but got ignored.