After a shaky start, the sci-fi channel series Sanctuary made very good use of green screen, to the point that in the last season you often couldn't tell the green screen from the physical sets. [yt]http://www.youtube.com/watch?v=iBz0uFQeTxY[/yt]
If you're not going to set it in space, why does it need to be Star Trek in particular? In fact - what is "it" that we're even talking about at that point? If Fringe is the model for being popular and cheap, why not do a spinoff series of Fringe? (Not that Fringe is "popular" given the ratings its been getting - which means it's not likely to serve as the template for anything.) If the idea is to shape a Star Trek series in the mold of a popular genre series, that is getting great ratings by the standards of wherever it lives, then here are the more likely candidates: The Clone Wars - CGI fest aimed at kids on the Cartoon Network. Game of Thrones - elaborate plotlines with grandiose scope focused on Federation politics, diplomacy and war, more morally grey than usual for Star Trek, made for Showtime or Netflix. The Walking Dead - ultra-violent space combat against horrific aliens (the Borg, revived and no longer treated as a joke?) with intense focus on a small band of Starfleet characters plus alien allies of conveniece, once again more morally grey than usual for Star Trek and made for Showtime or Netflix. Those are three distinct ways of possibly adapting Star Trek to audiences that already support shows that demand higher than average effects budgets, while still allowing the show to retain its identity. In the case of the last two, the shows will work on outlets that CBS either owns (Showtime) or has a good working relationship with (Netflix).
Falling Skies - Family friendly sci fi with limited use of special effects, a famous producer's name behind it, and a popular tv actor starring.
Yeah, that's another possibility - focus on a Federation colony under attack by mysterious aliens. You could have family groups and Starfleet characters, and have some episodes still set in space (the attack could be against a group of colonized worlds or there's a nearby Starbase etc.) That idea could be merged with The Walking Dead. Either way, it would be good for basic cable. The distinction would be the amount of violence allowed. On TNT or USA (or even SyFy?), less violence while on AMC or FX, more.
Guys.... it was 18 years between TOS and TNG. Yeah, there were a few films in between. But people are going on about how it's already been 8 years since ENT, so if it hasn't happened by now, it probably never will. Again, 18 years!!!!