I just got some inexpensive Schlage round ones (mainly because they matched my 1950s knobs better than anything else). They function well.

Spray paint the knobs and then give them several spray clear coats.

I ordered these from directdoorhardware.com in ORB (correction, VINTAGE BRONZE not ORB) and they are holding up great after 2 years (correction 1 year not 2). I had one defective set and they shipped a replacement pronto even though I didn't request it until 3 months after the initial order. They have many kinds of knobs. Mine were about $17 each.

AR102US11P Sure-Loc Arapaho Egg Shaped Knob

We replaced all our door hardware in our last house (satin nickel, not ORB) and got all the hardware from ebay. The locksets were all around $10 each, and the quality was good. The seller was josephdsmithjr.

Edit: I painted all these knobs the same way. The first one is the linen closet knob, which only my wife and myself used. The other two are on doors my mother in law often used, with the sponge-like brace on her thumb. After six months, that brace just wore off the ORB paint and clear coat. So that's why I decided to just buy the actual knobs. She'll be back again for another few months periodically, so it doesn't make sense to continue to repaint the knobs.

Thanks for the tips on alternate places to buy! Just for fun I'll post a few pics of the handles I painted a year ago.

@Scrappy25

I looked on the website you recommended. One of the comments under the ORB knob said the author of the comment had spoken with a rep at the company regarding the difference between the ORB and vintage bronze finishes for the Secur-lock brand and the rep said the ORB finish would develop a "patina" over time. That's something I wouldn't necessarily want to happen, I'd prefer they remain darker, closer to black. Have you had the knobs long enough to tell if they DO actually change?

Oh- I just checked my order and two mistakes on my original post- I did get the vintage bronze, good thing you asked! They look dark just like the ORB to me, I don't remember why I chose the vintage bronze since I did not know the information that you just posted. They've been installed for a year (not two) and I have not noticed any difference. I can try to get a picture tomorrow at home if you'd like. They look the same color to me as the ORB hinges that I used.

BTW I really like the egg shaped knobs- besides being cute and different, they are so much easier to open than the round ones, without the "catching clothes" and "dog opening doors" problems of levers.

I appreciate that DDH has all the needed specs on the knobs listed in a nice diagram. Make sure you measure your backset and bore. Our original crossbore was only 3/4 inch and this knob (and pretty much all other knobs now) needs an inch so it had to be enlarged. There is a door knob drilling kit from HD/lowes that you might need that includes the drill bit to enlarge the crossbore (you need 2 people, one to hold the door and one to drill). I also bought this knob because the faceplate was removable and I did not have a routed location for the faceplace on my door. Once the crossbore is the right size the installation is trivial. PS I learned all this information by first buying the knobs at HD without research and realizing all the reasons why they would not work. HTH

I gotta say, those knobs look pretty good painted! Well, the one that is still painted, anyway. I think you might as well go for the new knobs. You'd probably have to scuff it up to get paint to stick better and even then....

Yeah they do look great when the paint stays on! And I think probably, with normal use, the paint option is viable. It didn't take much time or effort to paint them, either.

@Scrappy,

I'd like to see a a photo of the vintage bronze knobs on a door if you didn't mind.

Here ya go. I tried to include the ORB hinge also.