From the author:
Patched this together on request, M18x R1 BIOS A05 (unlocked) with the RST 11.5 OROM.
The orom comes from the station-drivers site, not sure whether it will work fine with the M18x, though I don't really see why it shouldn't.
Btw, something's weird with the original orom in the R1 BIOS, the checksum is wrong... confusing.
Anyway, here's the BIOS, let me know how it performs. Also remember to use the latest RST driver for this ROM.
Flash with your favorite BIOS utility or the tools provided by Dell.
As always, use at your own risk..