Jackson necks are usually very thin... almost Ibanez Wizard thin, but they do have thicker profiles which can be ordered. Most Jackson players prefer thin necks.
I just built this on about a month ago... was my first Jackson, the only origonal parts left are the trem and body. This is pretty much the FASTEST neck Ive ever played, very thin and VERY slick. Pickups are Duncan JB TB4 and a Duncan Jazz 2 1kohm CTS vol pots, no tone. Not too thrilled with the Jazz though, probably going to swap it out for a '59.
Then theres my DKMG... Also very fast, super low action, not as fast as the maple one though, great for riffing. EMG 85 and 89 installed with push/pull pot to split the 89, tone pot, and EMG Active 20db Afterburner. Origonal Floyd Rose Bridge as well.
I dont buy custom shops... I build em. Wait till the new project gets finished...