)p( and myself have already experimented with trying the arcade models on other engines (including unreal). The performance was horrible.
Most of 3darcades models are extremely high quality, generally they have 5 times the polys of your average quake 3 player model. So with that said, I'm not sure what you mean by higher quality models. The quality of the model is only limited by the author of the model in 3darcade. We have access to lightmaps, reflection maps, animations ect... about the only thing it can't do is bumpmapping, which is useless when modeling smooth arcade cabs.
Plus to be blunt, unreal is not a front-end. It'd be difficult getting it to do things like launching external apps, make gamelists, ect.