All those makers will make fender pocket neckat standard prices, no additional charge. they'll also make them from any woods you wants with any construction. If you're going mahogany, I would recommend getting a 5 piece neck made with the fillets made of a brighter wood like maple. It counteracts deadspots and will stop the mahogany making things all woolly and muddy. also makes the neck stronger.
If you really want to go overboard btw, you can buy some threaded inserts and use them to attach the neck. Its a bit of work, but it makes the join much stronger and thusly increases sustain etc.
Stainless Steel guitar neck fixing kits