Since this seems to be the right thread, I'd like to ask how to get the requisite powers for Constructor without being a Shaper. Are there any shortcuts / dirty tricks I can use?
You would have to take 2 expanded knowledge feats. The first one is to get astral construct and the second one is to get psionic repair damage. That eats up 3 of your 5 feats (including boost construct) before level 7 when you can take your first level of constructor just qualifying for the prestige class. But if you are willing to make that investment that would work.