Hmm sounds like you're close to where I am - but...
You've still got the P&V dll problem?
and
You have no .NET in ROM?
Can you try these two packages in your build and see if it all works out?
(2.2MB, added .NETCF2SP1 to Helmi's addons)
http://schettino.us/john/ppc/Helmi_Addition.zip
(1.4M, swapped out bogus dlls with good ones for P&V)
http://schettino.us/john/ppc/MouHid.zip
Move your existing folders out of your OEM folder, save em! Copy these in - build & burn. If it works, then you've got the baseline ROM with .NET2.0SP1 and the Pic&Vid DLLs correct in ROM.
If not, I would love to know.
When you added your packages, did you put them in seperate OEM packages, or did you lump them all into one?