Nice pics, but as you said HUGE!!!!! Looks like a fun project - start a thread in the hardware section.
I've had another look into this and it all seems too easy.
Rather than BartPE, MicroXP is the way to go (Google it). It's a 99MB ISO, installs in under 5 minutes and you can install all the correct drivers for your hardware.
Then, using the great guide rare_j posted from lelezetec, it will boot directly into full screen WinUAE VERY quickly:
It almost seems too easy to do!!!! But here you can have a fast booting Amiga x86 with the power of WinUAE, for virtually no cost if you have old hardware lying around. An Atom powered ITX would work well with this setup. I'm going to try this soon with my ClassicWB packs.