Here's my 2 cents
BWC is really the only lab I trust around here anymore but then again all I really ever do there lately is have them process E-6 for me. They do offer some very good quality "high end" prints, as the old saying goes "You get what you pay for"
"Film Depot" on Central Expressway in Dallas is about the only place I know of around here to get that readily have 4X5 film. They have a pretty good selection of paper backgrounds on hand too. I have done a lot of business with them over the past five years or so and will continue to do so.
"Mesquite Camera" and "Garland Camera" (same ownership) does a good business but they no longer stock large format film and their medium format selection is somewhat thinned out. They do tell me they can order anything I want from their suppliers. They still have a good selection of Ilford & Kodak papers & chemicals on hand.
"Warehouse Photographic" in Farmers Branch has always had a plethora of darkroom and studio gear. They also have a good selection of fairly priced used photography equipment as well. I have bought a lot of used equipment from them over the years and have never had a problem.
I haven't been to "KEH Camera Brokers" in Richardson for a very long time but they always seemed to have a lot of 35mm and 4X5 equipment and even some darkroom swag.
I no longer do business with "Competetive Camera."