A go-to, versatile studio guitar? Hmmm.....
1. Double-cutaway for most comfortable access to all registers.
2. Should be at least somewhat symmetrical in appearance - not too skewed from one side to another or with extremely "pointy" horns. Example: Yammy SG-2000 = TOO symmetrical & plain-jane, Jackson Soloist = TOO asymmetrical. Apart from looks, big long top-horns just weigh the neck down.
3. Carved-top... no one ever bitches about a carved top. They're comfortable to play for just about anybody. Just don't make the carve so steep that it doesn't allow for good palm-muting when necessary.
4. TOM-type bridge w/stop tailpiece for better overall substance & tone. The bridge should be able to sit fairly low in the studs, so the neck angle would determine this. Depending on how far back you place the tailpiece, it could even be "sunken" a bit - that would allow you to get a good angle off the bridge, and would be kinda unique, as well (but would admittedly require another routing step). May as well offer a vibrato bridge option, too.
5. Binding along the fretboard, because that never seems to bother anyone one who's used to Fender-style necks, but to not have it often annoys Gibson-style players.
6. Neck should be somewhere between an early-60's SG
& a PRS baseball-bat. Not too thick, but not so thin that it's thumb-fatiguing to play. Width should be wider than a standard Fender, but narrower than a shredder Ibanez. Radius could be in the 10" to 12" range, perhaps? A comfortable compromise for most. Or if you want to get ambitious, a progressive radius might be very nice!
7. Fretboard should be Ebony. Hard enough to find on fretboards anymore, so make it the best. Cleanest tone & fastest/most accurate for any player, even if they've never played on it before.
8. Frets = Medium-jumbo... high enough to get good bends, but not so high that you may as well be playing a scalloped neck.
9. Pickups should be back-mounted and the guitar should come with a separate set of true single-coils (no coil-tappage here) that can be switched out with the 'buckers with a few screws and a 2-wire plug for each p'up. I think 2 p'ups would suffice in most cases, but you could offer a 3-pickup option for addt'l money & you might sell a few of those, as well. I think this back-loaded option (as long as whatever price-point you decide on includes both sets of p'ups, and if it were me I'd include a fifth pickup - a Tele lead - in with the price target) would go over better than coil-tapping options, or active electronics, etc., for a studio guitar. If you can figure out a way to do it WITHOUT screws (a recessed quick-release latch of some kind?), then that would be revolutionary
, and might be a big selling point!
10. Single-volume, two tone controls - volume control should be placed in an appropriate place to allow swells/quick changes that would apply to all pickups at once. Pickup selector switch should be below (when holding the guitar) the volume control - kinda like a Strat placement - you can slap it with your pinky there & change pickups instantly without missing a note.
11. Tuners = Locking Sperzels on all models, why not.
12. Construction should be: Maple Top, 3-piece Maple Neck, Mahogany or maybe even Shedua Back... best combination for balance, stability, and tone on a guitar of this type, but it should also be a little thinner than an LP, if possible, so it's not too heavy for some people's taste... should be easy to do as long as you employ an angled toggle or a standard knife switch for pickup selection. Only friggin' reason an LP has to be as thick as it is is the damn pickup switch. Chambered body option? Maybe a couple hundred extra if you want to offer that. Alder or Basswood body option? Dunno, I guess it depends on the final shape of what you decide to go with, and if it's going to balance well that way. Stick some binding around the top edge to go with the neck... back should be contoured to fit into the ribcage when seated.
13. Headstock needs to have a volute in the back - sometimes shit falls off the stand in the studio even when people are being careful, and you don't want a bunch of your guitars going around with sheared-off headstocks repaired by Elderly Instruments or bitched about all over the web by Ed Roman.
14. While we're on the subject of the headstock, make it a six-in-line for better alignment with the nut, and ease of tuning/string changing while on the clock. But, NO POINTY HEADSTOCKS! lol
Fret markers: Do something cool, but subtle... no need for big, distracting blocks/trapezoids, but maybe something more than just dots to give it a "signature" feel - maybe a little circular logo design with the initial of the name of the guitar in abalone.
Neck finish: I know you hate oil (we've talked about this on the phone not long ago, as you may recall), but would you at least consider Watco as an optional finish on the neck only? Tung is too sticky/gooey, but three or four coats of Watco simply RAWKS!
Would you consider installing a built-in DI circuit? Or at least offer that as an option? I personally wouldn't use this, but I'm just wondering if it might help sell more units! A separate jack with a built-in DI circuit would be pretty unique, and might be an attractive feature for studios who are recording a lot of direct guitars & using software for amp-ulations.