I've never found anywhere to do a short run of 3" CDs.
3" CD replication is always more expensive than conventional ones.
There are 2 ways they can go about making them:
- injection-molding the plastic to exactly the 3" size
- or pressing a standard CD, then literally cutting them down to the smaller size
Most places go with the cheaper slice & dice option, but either way is an extra step in the process, and thus more money. In addition, fewer places have the technology to do either than ever before. They were never very popular outside of Japan. Why? Who knows. I think they're a terrific format. But even I had to go with 3" CD-Rs for a recent EP release. And even those are getting harder to find.
I wouldn't necessarily shy away from the 3" CD-R version, however. They are much less scratch-prone than their larger cousins, and the ones I found were high quality & made by Phillips (the people who invented the CD).