Good stuff, think ill just pay Ł34.99!!
I think it has just worked for me.
First I had to create a new webmail, then I created a new Xbox live account with it and set region to China.
After that I had to fill in zip code info (found using site from a Google search for area codes in China).
Once I had the Xbox account set up I went to my webmail and verified the it via the email link.
Next I went to the download page for the game (linked earlier in the thread) and clicked the link to buy - I used Google translate to see what was what.
It asked me to verify the purchase with a code it emailed me, I found the email in my webmail spam folder - a six or eight digit numeric code.
After THAT, I went through to the sales page and filled in more name details etc (all in Chinese again but I used translate) - the most important bit on that page was the zip code.
Once I had that done and saved the details I got the 'w00t! purchase successful' popup.
Logged into new account on Xbox 360, downloaded new profile and game is currently downloading.