OK, then shoot a pre-sales question to wiredtree's or dedicatednow's sales dept. They are really good; just make sure they'll include all the support for what you need. I've used them in the past, and they're really good, even for things I can do myself or can delegate to someone that performs server management for me with non-managed providers.
Edit: And the reason I assumed you had no experience is because things like MySQL install, Apache and PHP build can be performed from within WHM even if you get lost at the command line. The hardest tasks IMO are the manual optimizations and tweaks to the DB, and the installation of required modules and additional software - ie. FFMPEG (if you don't know what you're doing).