Update: A repack is now released for the 1.61 as there was a small bug fix for the ix161-934.bin file.
C4Eva and TeamJungle have now released LiteOn iXtreme v1.61 (for Lite-On 73850 / 83850 / 83850v2 / 93850 drives) which adds support for waves 4 and 5, and Arakon of XBoxHacker.org has shared iXtreme v1.6 Non-Stealth for the XBox 360 console.
Download: LiteOn iXtreme v1.61 / iXtreme v1.6 Non-Stealth
It's important to note that currently both relases are NOT safe to use on XBox Live.
The LiteOn iXtreme v1.61 still has all the stealth features, but as mentioned above with modified checks to also allow/boot Wave 4 and Wave 5.
The iXtreme v1.6 Non-Stealth is modified non-stealth version of iXtreme v1.6, which to quote, is: "Patched to always act like if activate.iso was inserted, so blindly loads PFI DMI SS and goes on."
More PlayStation 3 News...