A quick update here to let everyone know that the Kickstarter for Secret Weapon Miniatures' Tablescape boards!
The link to the kickstater
These are some excellent boards produced by SWM and are setup to be completely modular 12" x 12" squares. The possible combinations are huge. Currently, the scrapyard tiles are unlocked which should suit most of your sci-fi wargaming needs. These appear to be a major improvement over GW's boards both in terms of variety, how they connect, and perhaps most importantly, cost - 40% cheaper than that other board currently available! Head on over to the kickstarter and support this awesome product!
(Pic from Secret Weapon Miniatures. All rights theirs.)