I'm sure there are many. The problem is how many are willing to do it right? You need to be asking some very specific questions and have the process written into the contract. In order for a barrier coat job to be done correctly there are a few very important things to consider and applies to epoxy based barrier coats.
ALL the paint must be removed. This means absolutely ZERO paint left on the bottom.
The hull, even though old and sanded/scraped, should then be thoroughly de-waxed using the proper de-waxing products.
The hull should be dry. This means no appreciable moisture. A barrier coat will seal in any moisture so you want it as dry as possible and this can take sometimes take months if your boat has lived in the water year round.
This job should ultimately be done INDOORS in a temp controlled environment.
The three plus coats of barrier coat and the first coat of bottom paint MUST be hot coated! Hot coating is the application of the next coat within a specified time window before the previous coat has fully kicked off but has achieved a specified level of cure before the next coat.
Hot coating ensures an actual chemical cross-linking between the coats of epoxy and the first coat of paint. This part of the job should be written into any contract and you should be on site to monitor this to make sure it happens. This prevents peeling and the need to wash amine blush off, and sand between coats!!! Even if you do wash and sand between coats you will NEVER get the bond you get with hot coating.
If your boat is a bolt on keel it should be properly stripped, primed and preped for the barrier coat. It should also be examined for any signs of leakage. If there are any signs of leaks the keel should be re-set at this point. If no leaks you should consider having the keel torqued and then the joint wrapped with glass & faired. This will prevent any future visible seams and will permanently seal the joint from the exterior.
I would advise your first coat of paint being a high quality copolymer ablative, of the same brand paint as the barrier coat used, Micron Extra or Micron 66 are great choices if using Interprotect 2000E, as many yards do. This first coat of paint can also be of a differing color than your final coat so you know when you need to re-paint. If this is all done properly you will most likely never see chunks of bottom paint flaking off your hull again..
Done right this is an EXPENSIVE undertaking to pay to have done. My boat is in the shop, as I type, for this very same thing. I have done four bottom jobs on my own boats, as described above, and have sworn it off for good. I now pay for it. The bottom job for our 36 footer will run about 5k.
This is what can happen when you don't apply a barrier coat correctly:
This is the moisture content of my hull as measured last week after sanding. It is about .25% - .50% moisture and this is considered well within the dry range for applying a barrier coat. Readings using an ElecroPhysics meter should be below 10 before barrier coating.