Okay Daddy Warbucks, get out your wallet and let's get busy.  You probably don't have the time, desire or abilities to make your own stuff so let's stimulate the economy instead. 

I must make it clear I am not endorsing any of the vendors below.
 

Hobbycraft, Inc.
800 E. Dimond Blvd Suite 136
Anchorage, AK 99515-2048
(907) 349-5815
(907) 349-3812 (FAX)
Modern rolling stock, cabooses and locomotives; call for current list and price of stock; mail order is available Hobbycraft@gci.net
 

The Milwaukee Road Train Shop (highly recommended by Jeff McCrea)

Robert Engelbach custom makes and paints Alaska Railroad gondolas, diesel locomotives and cabooses in HO scale.
 
 

Thanks to Casey and Pat Durand, Curt Fortenberry, and Randy Thompson for providing this information