Baseball America is reporting that the Astros have signed Dominican SS Jonathan Mejia for $370,000. He apparently has a good bat, but will be moved to either 3B or the outfield.
The Astros have also been linked (by Baseball Prospectus) to another Dominican SS, Jean Carlos Valdez. Like Mejia, he's likely to move to a different position. He's big and lanky, but is likely to add power as he fills out and matures.
Furthermore, Dominican RHP Jochy Ochando worked out at the Astros facility sometime this season. His velocity had dipped dramatically, down into the mid-80's. Rumored to be signable in the neighborhood of $500,000, he is also being looked at by the Dodgers, Rangers, Padres, and Mariners.
If you come across any other rumors, signings, or scouting reports, feel free to collect them here in the comments!