Ooo, Rexy Ice cap would be great
By the way, the PC version of the game (Sonic & Knuckles Collection) had different music for Carnival Night, Ice Cap, and Launch Base. It fills my heart with sadness that no one has done a remix of any of these versions, since the PC game is the one I always play, but it's probably too late in the project to consider at this point. However it could provide an alternative to doing yet another remix of the Genesis Ice Cap music so I thought I'd mention it.