Here's a few pics of the pier that Brendan mentioned. I went as big as I could afford which has worked out for the best. I was planning on an AP Mach1 / 900GTO but ended up with a MX. Either way, you can't go wrong with a pier that exceeds your current requirements... it will serve you into the future.
http://db.tt/N1aq7N5l
What you can't see from the pics is the floating top plate. This top plate is connected to the pier top plate by 4 x M16 bolts. I am currently getting the floating top plate tapped to accept the MX base plate knobs (4 x 3/8" @ 24TPI). Again, as Brendan mentioned, with a change of mount I can always get a new top plate cut and tapped.