My colleague Manoj Iyer has written up a guide on how to download EDK II and build the UEFI firmware for QEMU. This requires older versions of gcc found in Natty (since the newer Oneiric version is more pedantic and uses -Werror=unused-but-set-variable by default).
With a chroot I was able get it downloaded, built and tested in less than 40 minutes. Here is a sample UEFI helloworld application running in QEMU using the firmware using Manoj's instructions.
Now I can rig up some tests to exercise Ubuntu and the Firmware Test Suite without the need for any real UEFI hardware..