Pretty much any engine shop with a guy in his 40's or older will be able to rebuild a 454. If you know any off-road groups in the area they may be the best folks to ask for local recommendations. These guys will have similar requirements to you in regards to torque curves and powerband. If you ask somebody who enjoys old musclecars, they generally build for different conditions, and may not give applicable advice.
If you're looking for long life, make sure to add in a crank scraper and/or, windage tray and have it bored using a torque plate. I wouldn't go as far as balanced/blueprinted for the application though, that's expensive overkill. Make sure to specify the fuel octane you want to use as well, since the pistons are based off your compression needs, and that's mostly based on the fuel used.
A good engine guy will ask you a lot of questions about your intended usage.