Hi CD, boy for the requirements you want, this is a tough one. The price range you stated will kind of limit your choices. Most modern doubles in this price range will have SST/SNST, some kind of BTFE and if tubes will have that buldge.
One option is to either have one of your more "modern" older doubles tubed by Briley with their thin wall tubes (no buldge) that are rated for steel. If the shot size your using is on the smaller size you should be ok with regards to any rib seperation.
Or you can see what's on the used market in the way of a good Spanish or lesser known Italian maker and then have it tubed by Briley. The the cost of the gun and tubing would run you about 2k.
That's about all I can suggest. I hope someone else will come to the rescue for you here.
Anyway, best of luck to you in this most interesting search!
Greg
