I tried doing the Baby Park course as a battle map, but I couldn't get DLC courses to work for some reason. Always crashed? Loading the model is super slow anyway so I didn't have much fun with it.
Anyway, I modified the battle BYAML of GCN Dry Dry Desert to limit the track to a smaller battle arena like section, placed all starts and item boxes in it:
I wanted to make the pillars crash down at the start and block the way out of the "arena", but funnily, the fall delay parameter makes the game crash in Battle mode, so I just placed many + some funny palms.
The water effect is still visible, but actually gone. E.g., you drive everywhere like on land. Removing the water surface needs some model or texture editing and that makes loading the custom model so slow at the moment, so I didn't care about it. It gives some nice stealth to opponents anyway if they're on the other side of the water surface!
I also have no clue why Nintendo didn't do this. It's just different object placement of new objects, like they also did in Moo Moo Meadows or Yoshi Valley to get no ramps / ramps accessible from both ways. Probably because Battle was hax0red into the game like in the last 7 days and the track designer on holidays.
Can somebody please test how battling is on it? The CPU of course sucks with it, I can't export new paths yet (no time to fully implement that yet).
You can download the BYAML here:
http://ray.syroot.com/mk8/courses/desertbattle/battle_muunt.byaml
Of course it belongs to Ggc_DryDryDesert