Perhaps there should be a location or method where beta testers can sign up for testing the 64-bit version?  Even if the testing begins 4 months from now it can be useful herding all the 64-bit testers together. 

From the Elemental for Dummies sticky:

"About a 64 bit version of the game, (6) the big advantage for 64-bit for Stardock is that they can address more than 2 gigabytes of memory which allows them to stuff a lot more visual effects, textures, and elements into the game as well as support much larger maps, more units displayed at once, etc.

(7) There will be a 64-bit version of the game but not upon release.

And in case someone is wondering about it, if you install the game through Impulse, it will install the proper version for your system automatically (installing the 64 bit one, once it's out, if you system can handle it)."