Thanks for this guide (and forum) OP - I used it to convert a WD HDD for my second Xbox 360. The HDD I used was a brand new 500GB WD5000LPCX, so you can add that model to the list of hackable WD HDDs :D
WD5000LPCX & WD5000LPVX seem to be easily available at the moment, so no need to hunt down...