A new version (v1.61) of the iXtreme DVD Firmware for both Samsung and BenQ DVD drives has been released. A Lite-on version is still in development and will be released later (NO ETA).
These were released without any type of readme or NFO, but early user reports claim they work fine like v1.6 with added support for 'Wave 4' discs.
*Update* Team HyperX now officially released the new firmwares and the readme/nfo confirms it comes with 'Strict' Wave 4 compliance:
Note for unofficial releases:
It is highly recommended that you do not flash unverified or unofficial releases. We often do not implement specific security features in beta firmwares that are neccessary precaution's to help keep everyone as safe as possible on Xbox Live.
Official Site: n/a, by Team HyperX
Download: n/a (might be illegal under DMCA/EUCD)
News-Source: xbins.org, #FW@EFnet