Baikal seems to be the only player in town and while they have solid equipment, their customer support and ordering sucks.
Demand is through the roof so this market seems ripe for the taking.
Why has no one else developed a solution? All you would need to do is have a legit site with basic cart/ordering functionality and you would be in serious business.
...and truckloads of money for chip R&D and so on.
Besides, why would anyone sell their golden egg laying goose? Even if some people would make a more efficient miner for X11m they'd likely sell them once they're done mining with them.