A focusable line laser will improve the scan result.
Regarding the color: I prefer green, it's better to see for a color camera than red and not so expensive as blue lasers. Its line width can thinner be focused than red ones:viewtopic.php?p=1393#p1393
Power: 5 mW is fine for objects up to 1m.
From where to get: You are probably living in the U.S., so it's very difficult to import good lasers from abroad because of very strict import rules.
But here are some U.S. DAVID resellers:http://www.david-vision-systems.de/inde ... of+America
PS. If you intend to test DAVID with cheap line lasers, so have a look on Apinex.com lasers.
Edit: I have just taken a look at the DAVID US resellers sites.