The best technical system that I know of is the stackless python one developed for Eve Online, which I believe is profitable but has only about $300k players. Mind you, with that number it's insanely complex already. I had to stop playing, because to do so well requires the same level of commitment as a full time job.
However, one of the big killers of MMOs is problems with the launch. With some of these large high profile failures, they've already gone through this and worked out at least some of the bugs, so one would assume that this would make them more attractive to buyers.
we term it a platform, as its something to build with an upon. all of the projects we've seen require extension and addition to the basic model we've defined to customize it for the project at hand. but we've baked in things that make doing so trivially easy.
The fact that the article fails to mention them probably indicates that they aren't worth mentioning, though.
That's somewhat surprising to me. There's so many MMOs out there that have failed for one reason or another that you'd think someone would be trying to salvage their sunk costs by selling the engine.
Despite the competitiveness of the MMO market, there are still a lot of companies trying to break in, so you'd think that there'd be a decent sized market for a product which would shave years off of the development time.
I wonder if part of the problem comes from most MMO companies clinging to life for as long as they can, and then not having the money to rework their technology into something suitable for a third party. Certainly, there have been quality(from a technical standpoint, anyways) games that got released, got a few rounds of post launch patching, and then died from lack of users. I'd bet that with a bit of polish, that sort of proven technology would be a moneymaker.