I'm going through the same issues. Here is a post that I found on a blog site. I hope it helps.

http://www.designsponge.com/2010/10/top-10-hardware-resources.html

On some doors you only need "dummies" like the closets. You won't need inside knobs. Keep in mind that the knobs may not have to match on all the doors. Depends how you are looking at them.

Also, have you tried ebay?

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l2632.R2.TR5.TRC2.A0.H1.Xvintage+glass+door+kn

Besides ebay as JudyG recommends, you can find faux vintage doorknobs on Amazon.com from a multitude of sellers. You might also try salvage places to see if they have any from old doors. If they don't, you can always ask if they know where you could find some.

We used vintage knobs from ebay for our house. We also had to buy the inside piece as you mentioned. We had them installed by a handyman (my dad!!) and he had to put some wood fillers in some of the holes that were too big for the knob. We were very happy with them. But, when we did our addition, we bought matching emtek old town knobs on the new doors and loved them so much we ended up replacing the vintage ones with the new emtek knobs. The old ones made noise, weren't smooth, which we realized after seeing the new ones!