Well.., a couple of ways to approach it.
You can certainly order a "Custom"..., and several of the makers that deal with
-EDC- knives will make you 3" model. You could give Duane Weikum (owner of EDC) a call, and get on a waiting list.
That option is around $350-$400 for something utilitarian, and not too fancy.., but Duane may also have some old Pacific Cuterly or BM 3" models available that are in good shape.
Currently.., there is no production model out there that is 3"..., but you can probably find a Benchmade Model 31 on the secondary market for maybe $175+ MINT. That's a Ti-Handled model, drop point blade, pocket clip. Very light.., and very popular..., simply not produced anymore unfortunately.
There are several other options out there in regard to
searching. Ken Largin made many custom models with 3" blades in the mid 80's.., and now and then they show up also.
The follow-up production knife to the "Spyderfly" (the "Szabo-Fly")..., will supposedly have a smaller version following the large model (the larger soon to be released), so you may want to take a look at the blade style to see if it's something you'd like. I'd guess they'll run around $100 once released, but I can't remember if Spyderco published a blade length on them yet.
If you could live with a 3.6" blade..., Bradley Cutlery has just released a few protos. Very nice knife (I played with one yesterday). 8.5" overall....Ti-Handles, S30V bladesteel..., and a nice pocket clip.
Duane should have some of those shortly..., and they'll be somewhat over $200....