This early beta was found on an Xbox debug kit. From what I can tell, the closest approximation for the build date is January 6th, 2006. The game includes 3 different .XBE files, and this seems to be the last date. If it holds true, this build is 3 months after the retail release on the Xbox, and 9 months before the PSP version. My theory is that this build is an early version of Rush for the PSP, running some hybrid code on the Xbox during the porting process.
This is among the strangest of the titles that I have received over the years. It runs, mostly, in a small window, which looks to be PSP-sized, which, when you also look at the Playstation buttons, supports my theory. The game is also 1.4 gigs, which would fit on a UMD.
Unfortunately, the game really doesn’t do much as you can see. It loads to the Rush menu, with most functions being disabled. Quick race is selectable, with a list of the tracks, and an early car select menu, but past that, it crashes with a dirty disk error. Don’t adjust your speakers either, sound is totally missing in this build, which you can see in the video located below.