I have been looking at a few vintage 10ga doubles and they are all chambered for the 10ga 2-3/4 shells, I am not a re-loader, is there any company out there that makes shells in that length?

Common chamber lengths for the 10 gauge were 2-5/8" and 2-7/8". RST has a few loads in the 2-7/8" length.

http://www.rstshells.com/store/m/1-10-Gauge.aspx

Not directly your question but you will find the short ten to be a very efficient cartridge. Beautiful patterns and delivers all the shot charge anyone could reasonably desire.

My Parkers and Lefevers have 2 5/8 or 2 7/8, my Remingtons have 2 3/4. As suggested RST 2 7/8 won't hurt a gun made for 2 3/4. It's a shame you don't reload, especially for the short ten. It would be so much cheaper and any load would be at your finger tips. Maybe give it a second thought ?

And, in any case, save your hulls

I buy Federal 3.5 empties and cut them down to 2 7/8
and load with the appropriate green dot load

I have a Lefever 10 gauge rod cocker in the 10K SN range which has a 3" chamber in it. Prior to WWI most American makers would chamber a gun to most an length desired, mainly in 1/8" steps from 2 /12" to 3 1/4", with 2 9/16" thrown in to boot. 8 gauge was available longer than the 3 1/4" length. I am not sure if there were any 3 1/2" tens made prior to the Western Arms/Ithaca NID connection or not, but if so they would not have been for "Magnum" loads just longer wad columns with standard loads as was the early 3" 12 & 20 gauges & possibly even some 16s.

All of the American made short tens I have encountered have been chambered 2 7/8". The sellers might not have adequate tools or knowledge to accurately measure the chambers.

And if you decide you want to dive into the short 10's, I have an extra MEC 600 jr set up to load them. $110 plus cost to send. Loads a beautiful shell with cut down 3 1/2 inchers.

Specialty places like RST friend. With advent of 12ga 3.5" it's harder to find modern 10ga shells then 16ga ones.