Who are the most underground high-end companies

Taters, I've paid dearly for due diligence. When I finally swore off the high-end (I should say high-advertised) stuff was when I paid air-fare to fly the Vandy dealer over here to "adjust" the 5AC speaks, drove 90 miles each way to the airport and back, bought him lunch, the whole smash. He spent all of 10 minutes with some Radio Shack gizmo to "centre" the Vandies and the rest of the day trying to push some $8k speaker cables on me. We did a swap-out with my Blue Jeans and I found myself, in my own damn living room, apologizing, that I could not hear a difference. Then I had to drive him back to the airport. Took me about a week to realize I was very angry, and started looking in to how this stuff is made and through the channels it is sold. Like I said, find out how hard it is to talk to the guy who actually makes the stuff, and deal directly with him/her. It has cost me at least 50 large to realize that for under 10 grand you can get the best sound out there, American built, and it will just tickle your ears.

For speakers, you can't touch Tyler Acoustics. They will blow the doors off Vandersteen's best at about one-fourth the price.
If you're into tubes and ballsy amps, have a look at Tube Nirvana.net.
Don Sachs in Nelson, B.C. builds a preamp to die for and also rehabs the legendary HK Citations.
I own all these products, have no financial interest in their makers, but you can save a ton of money. Don't look for their ads in the slick magazines. These are all hand-built in one- or two-man shops, for the pure joy of it.

Yep. I owned a pair of Vandersteen 5A carbons ($32k), replaced them with a pair of Tyler Acoustics D-12x speakers for $8k, and like them much better. Depends on your listening needs. The Vandies are great speaks but their "sweet spot" is about one foot wide dedicated. Tyler's Decade line, at least the D12xs, will open up the sound staging until you're tired of feeding the band. Ty's in Tennessee, just phone him up and talk to him. The D12xs use Class D amps in the woofer sections but unlike the Vandies, which use an AB amp in a sealed bottom, the Decades are a ported, transmission-line design. My other shout-out to Tylers is they are very efficient and give incredible detail at low volumes. Again, I'm not on his or anybody else's payroll. It's a word-of-mouth thing.

I don’t disagree with your surmise, Taters. I’ve owned Vandies from the 2CEs up to the 5ACs. I hold Dick Vandersteen and his products in the highest regard. But I think if you gave the Tylers a listen you might see (hear) my point. You can’t go wrong either way, but why pay for dealer mark-ups, and ads and write-ups in The Absolute Sound? You would not believe how much money TAS and the rest of that rotten lot sweat out of guys like Dick Vandersteen. Ask him. Then talk to guys who don’t play that game.

Taters, there are a lot of good options out there. And since you started this thread looking for underground high-end, well, you’ve seen some great suggestions here from the other posters. I can get absolutely top-end tube gear hand-built in Montana or Nelson, B.C., or Massachusetts for 10 percent of what McIntosh or ARC would charge, and with better circuity. The math is pretty simple. The brick-and-mortar shops rake 50 percent off the top, then you’ve got to shovel $10k at Bob Hartley of TAS for a brief hoo-hah review. This sweats a small company pretty hard. I like buying from somebody who actually makes the thing and answers the phone and has no advertising budget (hence, underground). Wish I could give you better advice on solid-state gear, but my s/s stuff was built by the Bedini brothers 30 years ago and I can still call them up if I have an issue, which I never do with their amps, but they’re fun to BS with. Somebody mentioned Magnapans, they’re still around, you can call them up, the son or daughter answers the phone and hands you off to the owner if he/she can’t resolve it. I would investigate all the possibilities recommended by the other posters, not just me. My first recommendation would be to call ’em up (or email them) and see who answers and how quickly they get back to you. And don’t squander money on cables just yet. Start with Blue Jeans Cables in Seattle and work your way up if you really feel the need to. 

Hey brethren, I’m not saying one outfit’s gear is better than another’s. But electrons move in a certain, defined, predictable and unalterable way. Along that way their passage gets corrupted whether by tubes or silicon or wire resistance and capacitance. So it's your choice of which distortion you like best. But over short distances in a home system these factors are hardly, if at all, measurable. AB comparisons are nigh impossible in a show-room, because of the many other variables objective and subjective. A louder amp or a more efficient speaker will almost always sound better. All’s I’m saying is, get rid of as many middle-men as possible and you will come out ahead. That’s simple math. Checked your hearing lately? I bet if you’re 50 years old you can’t hear much above 4 or maybe 5 kHz, so why pay a premium for stuff that on a test bench with a scope can turn out 100 kHz? Inter-connects, i.e. speaker leads and the co-ax that connects everything, are just pushing electrons down, or rather outside, a pipe. The rest is snake oil.