I guess they decided they could make some money with the PS2 port, and probably figured 'aww, what the heck, let's port it to the box as well'.. so I doubt we'll see a cube port. The article mentions the possibility of a PC version though.. that would be sweet (I'd love to get some Outrun 2 action on my LAN).
Personally, I feel it should be ported to every system... the original Outrun has to be in the running for 'most ported game'.