Various sources are reporting that Stargate Worlds will be a single player game before it's an MMORPG. We've already seen one single player Stargate game fail to advance to market after having a prototype that was good enough to use on an episode of the show, but it seems that Cheyenne Mountain has a better chance of pulling off a single player game than an MMORPG given their funding situation.
At this point, I guess we can say that pulling a Torchlight is a legitimate business model - build the game engine first and use the cash from that to finance the network code, testing, and larger amounts of content that players expect in an MMO. The production values on the modern MMORPG are becoming large enough that this may be the only way for a start-up to get into the genre.
That said, it will be interesting to see whether the Torchlight MMO, and Stargate Worlds if it ever happens, will be influenced by having begun their lives as solo games. Will the engine work with large numbers of players, or will there need to be Guild Wars style single party instances? Fans of the single player version are going to be amongst the most likely customers for the MMO, so developers are almost certainly going to be pressured to keep the games solo-friendly at precisely the time when there's real room in the genre for games to hit the non-solo niche. In the end, this development model may have more impact on the end products that anyone realizes at the moment.
(Ironically, Massively has an interview with Runic Games on their work with Torchlight and its MMO offspring just as another studio emulates their business model, albeit as a last resort.)