It looks like the EB7500ATX port within the acorn32 stuff should be pretty close. Its
uses the same ARM chip although the IO address usage details are different.
You'd have to figure out booting the kernel, and the different locations of things like ISA bus addresses,
IDE interface, SuperIO chip differences, etc. between the two boards. Note the
ISA bus on the webpal is very limited in terms of boards it can support.
See the BBS for discussions of what few ISA boards people have gotten to work.
Search for EB7500ATX for info on that board and then compare it to the info on
webpal.bigbrd.com and the other Webpal Linux sites. The EB7500ATX also
has a Linux 2.4 port so that might give other clues on what is different.
I've never ported NetBSD to a platform so I can't help you on specific details
on how to do a NetBSD port.