urban_encounter: Talk to the folks at the Sacramento Archives & Museum Collection Center: http://www.sacramenities.com/history/
They print photos for various uses, normally producing two prints each time and choosing one. The others they set aside, and make available for sale. Most of the photos are 8x10 or 5x7 and are very reasonably priced--you just sort of have to flip through the boxes they have until you find something you like.
You can also order custom prints of any photo at SAMCC: they have a searchable online database of around 50,000 photos. Of course, that represents only about 1% of their collection!
Ordering a custom print costs more (you have to pay for the negative) but if you are looking for specific scenes it's a great way to do it, and a nice way to help support the operation of Sacramento's treasure trove of city history.