I'll write a full response here and add it to the FAQ, because its a fair question which is coming up often:
We are going to offer variants eventually, as well as the instant chat code they use at gilgatex's goondip, the problem is we have several times as many users, which really means we can't dive into adding new code.
If there's a 1 in 100 chance of something screwing up on gilgatex or jayp's server it'll happen fairly infrequently so there'd be no big problem, and things can be dealt with one at a time. But if there's a 1/100 chance of something screwing up here we'll have a couple dozen games crashing constantly (and things are bad enough already).
Also if on another server an update means a piece of code has to do double the amount of work it's no big deal, there's plenty of breathing room for expansion.
Here we're only just barely running with our constraints, and until recently we were getting daily crashes just due to overloading; pretty much all of the code I've been writing recently has been about trying to make things more efficient so we can keep running on this server, which makes adding code to do more stuff is hard right now.
e.g. with jayp's live code I just added it in without thinking too much about the difference in size between servers, and even though it's a great update it has caused a lot of problems which we're still adjusting to.
With adding variants and live chat I'll be taking more time to get it right and only introduce them when I think the server can handle it.
Finally jayp's system for variants is really rather kludgy as he'd admit, added bit-by-bit, involving many patches spread all throughout the code, which will make adding more variants as time goes on increasingly hard. The system we'll be using here will separate all the variant code out so variants can't interfere with each other and can be added without needing patches
Client-side orders, live-game efficiency improvements, caching, etc, are all steps towards efficient, stable variant support; it's taking longer but the server won't implode when we get there