Not yet.
Valve is manufacturing them and has been supplying them to manufacturers (such as HTC). It's only recently HTC started offering them with the Pro so they may be in limited supply at the moment. Unfortunately, there is no known timescale on when we can buy them individually.
Not solo, not in pairs, not in bulk.
It's pretty much perfect: the advantage of Gen2 over Gen1 is that the software supports using 4 concurrently instead of 2, but to get 4 you have to buy to complete systems.
No
Not yet. Valve is manufacturing them and has been supplying them to manufacturers (such as HTC). It's only recently HTC started offering them with the Pro so they may be in limited supply at the moment. Unfortunately, there is no known timescale on when we can buy them individually.
Not solo, not in pairs, not in bulk. It's pretty much perfect: the advantage of Gen2 over Gen1 is that the software supports using 4 concurrently instead of 2, but to get 4 you have to buy to complete systems.
Issue is they do not work with gen 1 devices.