The media slang NextBox is the best name IMO. Descriptive, catchy wordplay. Or stick with Xenon - a meaningless, generic name though still with the 'X' contingent. 'XBox360' is 'aloof'. What does the 360 mean? See, the only console thus far that I know of to actually have a numerical sequel is PlayStation. Nintendo and Sega et al creatd new names for new systems. We didn't go NES, NES2, NES3, NES4, nor did we go, NES, SNES, N64 without reason. N64 meant 64bit Nintendo. And also there were different names for different regions Sega Geneis = Megadrive, and SNES = Famicon.
I dunno. I guess I won't be able to accept a number unless it's justified, as either part of an already numbered series or a description of the system. If Sony went PlayStation, PlayStation 300, I'd still think it daft! Either come up with a new name (SuperPlayStation) or a standard sequel (PlayStation2)
If this takes off, will we see the same with films? Will we see a two part Kill Bill named "Kill Bill:Volume 1" and "Kill Bill:360"? Will StarWars be repackaged Episode 1, Episode 360, Episode 2000, Episode Epsilon, Episode GT 2000, Episode Googleplex?