Wow, nine responses after I saw this thing earlier today (before I had to run to work)!
I, too, was going to comment on Paul's wish list, aren't there only three C-430s left in existence? The former GB&W unit is at the National Railroad Museum in Green Bay as a static display (cracked crankshaft did it in, wasn't it?) and the Sesquehana has (had?) two. (Think they were sold/leased to another NE railroad).
NRE has some of the Minnesota Commercial's ALCo.s, or so I've read. At least the 424s and one of the RS18u units. Don't know what else of the Commerical's they would have, or what the MNNR still has that would be up for sale (and I doubt they're giving up the RS27s).
I would follow Alcochaser's advice and get a hold of Mr. Bowers... no doubt he has some "toys" he'd be willing to let you guys play with.
Good luck on your search.