Yeah, I have a 20GB HDD on my 360, and I ran into "Out of space" errors during the last version update. I plan to upgrade my HDD as soon as I can afford it, which will likely be at least a few months from now.

There is a very good reason why SE wouldn't make non-PS2 zones: it would effectively double the workload for them, as they'd have to maintain two versions of the codebase. Plus they'd have a TON of work to do with updating the graphics. The amount of work required isn't really worth it, IMO. Plus I really, really don't like the idea of players being restricted from accessing certain zones due to what hardware they are running.