I successfully changed the DVD key and region code of a 360. So it's all confirmed.
As for landmarks and interweb fame. All I did towards this was to reverse the plaintext KV signature to figure out how to modify and resign the KV contents. And even this work was built on the efforts of other hackers. For example, I didn't locate the region code in the KV and a lot of the SHA1 and RC4 encryption code was reversed and documented by others way before I started looking at it. *If* the region code tests are successful, then the following people contributed *much more* to this achievement than me.
Takires, TheSpecialist, Robinsod, tmbinc.
The following assumes you have the correct 1BL key and CPU key set in the flashtool.
1. Dump the NAND from the US 360 (528-bytes-per-page)
2. Open in the latest flashtool (v0.8) and click [extract]
3. Edit extracted KV.bin and change 16-bits at offset 0xB8 from 0x00FF to 0x02FE
4. Open in flashtool and click [patch], check the "patch keyvault" box and select the KV.bin modified in step 3
5. Click [OK] and choose output file
6. Flash output image back to the NAND of the US 360
7. Try an EU game or two.
