I should explain a bit more. Essentially my friend and I want to build baritones because we're interested in exploring new sounds. We find ourselves wanting to tune our standard-scale guitars down further than they already are (tuned to dropped-C), but then we began to think, Why not just build baritones?
While you can tune a conventional guitar down very low, this can cause complications. Intonation becomes a bitch. Staying in tune can sometimes be a challenge. If you want to go down as low as B or A, you have to use very thick strings, and for some that isn't an easy progression. And even with thick strings, sometimes the tension is very loose and "wobbly," even when set up by a good luthier.
I've recently gotten into guitar mods and repair as a new hobby. After 14 years of playing, I want to get more involved with actually making guitars. The baritone project is going to be one of the first guitars I try to put together from pre-made parts - mostly Warmoth stuff. So right off the bat we're looking at a bolt-on neck. It will most likely also be one body wood that we're talking about, because I like the idea of making a baritone Tele Deluxe (two humbucker design).
Pickups are another thread entirely, really. I am leaning toward a set of good passives, though my friend wants to use EMGs.
It's a bit tough to articulate exactly what kind of sound I'm going for. I'm not what many people call a "flogger" - someone who tunes down in a dropped-tuning just to bang away on big, one-finger monkey chords. I like heavy rhythms and complex chords, and I need a guitar that can deliver them with both clarity AND a sense of warmth. Sometimes clarity translates to sterility or an almost digital lack of presence; I hear this on a lot of thinner "shredder" guitars, like my RG550. The antithesis of that is my Les Paul, but the sound coming out of that walks a very fine line between being muddy and being articulate. So I'm looking for something that can deliver a kind of sonic density, with a very warm and organic low end, as well as non-harsh, almost piano-like highs. This is very important to me. Many guitars that are designed for "metal" players over-emphasive low-end chunk withou paying attention to the rest of the guitar's register. So you'll be playing chords on the high strings and suddenly everything sounds ghastly.
I have never been a "scooped" kind of guy when it comes to tone, and neither is my friend. In fact I have my Rivera Knucklehead 100 set up so that all my tone controls are over 6.
I'm also not one to adhere to wive's-tale philosophies on guitar design. I'm not automatically dismissing maple as the body choice. Hell, the more I think about it, it could work out well. But as you point out, why do what others have done? How often have you seen a koa baritone? Remember that half the point of building our own guitars is to satisfy ourselves and our own innate curiousity. The other half is to sound damn good.