Reading this again I realized almost nobody actually answered the question.
I would fork out up to $3000.00 for a guitar that really sent shivers thru me, that seems to be the upper end of most quality built consumer grade guitars. Beyond that I'd feel as if I was paying for something that simply wasn't a tangible difference. I realize there are many guitars beyond that range that still fall into regular Joe status but I just don't believe they are remarkably different enough to justify the costs in most cases.
I'm not an antique lover and elitism makes my skin crawl, for a guitar to be worth more than the current market value of it's counterpart it most likely is sporting some assigned status that isn't really part of the tangible or inherent value.
My first guitar is a hand built Strat replica. By me and a buddy who is very very good at his trade. It's worth much more than the sum value of it's parts to me but reality and truth suggest it's barely worth more than the sum total of it's parts. Perfect example of emotional value as opposed to actual value.
If I can't sell my "emotional value";

then using Spock like logic I can't justify buying someone elses.
There is a You Tube video of Jack White clunking together a really raw one string Diddely Bo. I mean salvaged paint peeling 2x4, broken bottle / crushed can stuff with common spike nails and some cooked pick up. Twisted wires and gum for tape type craftsmanship. He makes that thing sound amazing. Somebody would more than overpay for that thing and chances are they would drive everybody flucking crazy with the ungodly sounds it's capable of.