Rom Version: 1.11.405.4 (English)
Radio Version: 188.8.131.52_02.63.90
Bootloader: 1.11.0000 (Sep 12 2006 at 13:08:40)
You can find the ROM on XDA-Developers FTP:
For the curious out there, the ROM is shipped in NBH format so you can extract it if you want to look at the ROM components, the bootloader (SPL.nb 512K size!) has a lot of debugging information enabled as this is a Test release ROM.
EDIT: For those people having problem in updating to new Excalibur ROM due to Invalid Model ID error, that is due to bootloader version on Dash. You need to flash this bootloader first and then flash the Excalibur ROM. Also, this bootloader CAN be used for flashing new ROMs on pre-production Excalibur devices.PS: I don't own an Excalibur and I can't test it so I don't know what's on this ROM, if you try it please post details about it.
RUU_Excalibur_SPL-1.11_UpgradeOnly.exe contains bootloader version 1.11.0000 (Sep 26 2006 at 20:19:20).