Thought about a china bike?
/insert china bike hate here.
Seriously though. I picked up an Orion RXB250L last spring, I'm ~3800 all in for a street legal dirt oriented street legal bike registered for 2 years with a suspension re-valved and sprung for my weight. Did I spend a month wrenching on it when it was delivered? yes. It was office art for a month till I got it tagged. But that gave me time to go through it strip it completely down, loctite every bolt on the frame, adjust the valves, swap jets on the carb (they come stupid lean for emissions reasons, like every other bike), add anti vibe inserts to the handlebars (not needed, but I had them), Actual bark buster hand guards, seat concepts seat (a little carving on a KTM kit) and hydraulic clutch conversion. I ride with guys who ride the spectrum of bikes (KTM, Husky, Beta, big 4 jap manufactures) every one of them that have ridden it have stated for the amount I've got in it's awesome. Lighter than the Japanese bikes, but heavier than the euro offerings.
When I laid it down last year and snapped the shift shaft I was able to get the parts within 2 weeks. (one ordered off alibaba, and the other off ebay. Zongshen motors are everywhere now) Doesn't have the insane top end of the KTM/Husky/Beta, but for the single track and woods riding we do it's plenty of power. I even got nutty with it and geared it WAY down (it's begging for mercy at a gps verified 70mph on the road) but it will pop the front tire with 280lbs of me/gear/etc on it in first with the throttle, and a weight shift and slight clutch pop in second. (not a speed demon so I've not tried it in third as of yet)
Point is, they have a 125 with a 16/19" wheel combo for 1399 delivered with a 28" seat height. Or a 190 rated for twice the power and a 5 speed vs 4, and a 32/33" seat height for 1899 delivered. I'm thinking about picking up one of the 190's for playing in the sand, or may just pick up a used 150 2 stroke for a bit more. 90lbs lighter than the 250. (LOTS of sand here in FL, and it's one of the contributing factors to my lay down last year)
Orion is the only one I've dealt with. Bit of a pain to deal with because you have to email just about everything, but they do their best to make it right. I ordered mine unassembled because I knew I wanted to go through it bolt by bolt a few were missing, and I had them with spares in a few days after I emailed them about it. (loctite, and witness marked every bolt) But GPX formerly Pitster, also has a rep for doing what needs to be done to take care of their customers, (kinda nice emailing about a part for a motor and the company owner answers your email, and reaches out on facebook) and they sell some NICE machines. Their 300 4 stroke with the twin cam head is heck of a motor. Bike's no slouch either, definately more capable than myself currently. Their prices get close to the big 4, but I'm seriously considering dropping 10k on a 450 rally next year, especially if we end up moving to Colorado (fingers crossed on that one, SWMBO is on her second round of interviews for the position out there, that comes with almost 3x the paycheck she currently brings home).
Kid I ride with occasionally has a 250 Titan, bit smaller frame than my Orion, but same motor, he ordered his off amazon for ~2k. He has almost 2k miles of street and trails, rear tire is about worn out, he's already had to put a chain on his, but he's a LOT harder on his bike than I am. Stock sprockets on his, and he can cruise at 60-65 without worrying about it to much. Mine with the gearing change is much more comfortable at 50-55.
If you like to tinker, these china bikes are a dream come true, as you have to modify just about any part you want to put on it accessory wise. I checked my valves after the first ride, and had to adjust them, checked at 100, 500 and 1000 miles with no change. They're air cooled bikes for the most part, so I change the oil about once a month or every 3-4 riding weekends (3-5 hours a weekend usually, sometimes more) stop by the car wash on the way home, spray it down, grease ninja to lube the chain when I get home, shut the petcock off and idle it till it sputters out and put it away till next weekend. I clean my air filter every other week when I'm riding. (sand and mud). I've got my shock out getting professionally lowered. When it get's back I'd be glad to let anyone check it out if you're near Tampa.