Well I'm sure this is going to disappoint a few people but I'm now able to confirm that SSX was never playable on Dreamcast. While Dreamcast was the original target console very early on, prototyping was only done on PC. Console development didn't start until the switch to PS2.
From the executive producer:
I don't have that much to share on the topic other than very early on in the development of what became SSX we were prototyping in a PC environment initially thinking that it might make sense for the Dreamcast. However, when EA leadership was unable to make a deal with Sega that made sense for EA, we were told that we (as a company) would not be focusing on Dreamcast as a platform. At that point, we began to move our focus to the PS2, which I believe ended up being a better fit for what we were trying to do title.