No mention of Zone in your post leung, I guess it just slipped your mind. I think an easy way to present Racebox would be to keep the big arrow shape they have, but add another line, so it would go C, B, A, A+, Zone. Then if you select a speed category, it presents you with 3 options: TT, SL, Tournament.

Something Jan mentioned ages ago is online Zone, as opposed to Zone Battle. This would be awesome, although I guess it would have to be a 1vs1 thing. Would still rule though