I'll just say this right off the bat - it took me a while to get this quarry set up. Had to get a big reactor going along, (yellorium) and had to make redstone conduits - blablabla... But, this is the size of my quarry.
The quarry is 30x37, and I got some pretty good stuff from it as well. (I'm using the newest version of Tekkit)
What's the biggest quarry you've made?