I don't know about "going away", but I've been looking over other modpacks and launchers to possibly put up another minecraft server of some type. There are a few launchers that are releasing updates soon that do some pretty spectacular things, such as specifying the mods you want to run on the server, giving your users a code-hash to put in their launcher, which downloads only the mods your server uses, and in the correct versions. This would allow us to roll our own launcher, add mods when they're released (by updating the player launcher hash code) update mods as they update, individually, without the super-huge bugs and rumored huge community drama within the tekkit community.
Unfortunately the tekkit map won't be compatible, but I will probably not be taking it down, as it's been reasonably popular and has some dedicated regulars that have put a LOT of time into it, myself included.