After the news last week that Xcor's Lynx is not quite dead, the only serious Space tourism projects left now are Blue Origin and Virgin Galactic's (and I have serious doubt about the latter ever flying passengers, but that's another story). Could anyone else get in the game if the market shows there is demand?
First idea I had was for a quick and simple SpaceX Falcon 9 derived vehicle. Once reusability of the first stage and Crew Dragon are proved, why not put a Dragon on a F9 first stage and use for a RTLS (return to launch site) flight? It could be made lighter and simpler by removing the heat shield, docking adaptor, trunk and interstage. It might even be worth removing some engines as the thrust required would be a lot lower (maybe reviving the Falcon 5 name?), and cutting the stage down. (though it may be easier to build from scratch if you'd do this).
Sadly this is unlikely to ever happen unless someone was to ask SpaceX to build it for them, given Musk's focus on Mars.
The other idea I had was after reading this piece of Northrop's XS-1 bid. Their team includes Virgin, who presumably are building the upper stage (based on Launcher 1?) If they get the contract, I'd guess that Virgin would order some for commercial use launching payloads bigger than L1 can do). If the system proves robust enough, and SS2's performance proves a disappointment, how about putting a crew compartment on the back to carry passengers on suborbital flights? They could even use the SS2 cabin and fuselage as the basis to reduce cost and development time (I'd expect it to remain attached to the XS-1 throughout the flight unless there was an emergency, for which I'd give it a LAS and parachutes). If the keep the whole fuselage design they could enlarge the cabin to give more seats. Overall this would have the advantage over SS2 of higher flight rates, quicker turnaround times, lower costs and more passengers being flown higher (longer time weightless/better views).
Even if this doesn't happen, I hope NG get XS-1, build something that actually flies and can be scaled up.