Sigh.... I was going to respond but what ever update they just did to forum broke the replay screen some how on Firefox Nightly. So I had to go and install chrome just to reply to the thread.
Anyways so I wanted to test some stuff today which is how a stumbled on the unicorn.
Extra ulitlies added the Ender-Thermic pump which is a normal BC pump (power cost and function). But it replaces lava blocks with stone blocks. I wanted to see just how lagy or not this was.
I am Happy to report it is epic. There seems to be no lag difference or impact on the game when comparing a loaded nether chunk (3x3 chunk loader) while in the over world to a Ender-Thermic Pump running. No real liquid updates at all. And the only lighting updates happen fairly rarely after it has paved over a large area.
So Dave this might be an OK thing to use on servers to allow people that want to pump the nether dry to do so with little server impact.
Also there is a config option to allow its use in the over world. Don't really see how it would be any issue the mod page says it is disabled by default to stop greifing. But one I don't know many people that build with lava source blocks, two bucket of water would just as bad to those folks, and three if they are worried about someone filling someones home with lava there are MANY other ways to do so. And if the pack final version has those hot springs and volcano biemos with hundreds of pools of lava it might be nice to have this as an option for overworld use to.
just figured I'd share.