Currently we are using tekkit 1.2.7b without any plugins only some custom mods added like chocolatecraft or Infernal mobs.
Here is an example for the crashreports.
https://www.dropbox.com/s/f6hwb6d5qv277tc/crash-2014-02-28_05.46.39-server.txt
But i made a testrun with the vanilla tekkit 1.2.7b Server aswell, and got the same results.
The test was run with an empty Server, a newly generated map, no options changed in any of the configs and no plugins or MCPC+ used. Still, this setup used already about 50% more ram than the old Version 1.1.10 with a large world, with quarries and chunkloader. The actual numbers are about 600mb for the old Version and already 900mb with the vanilla tekkit 1.2.7b Server. If you need any more information, just ask.
Thanks for the assist