Cannon, sorry the discuss into your thread.

I think you must consider first what yield you will need, and design the cab according to that.

I think its far better a 400w HPS than 2 150w CFls. If you want to start with a little setup, to go learning, and use it as veg chamber in the future, its a good idea, but then think in a setup compatible with its future use.

I suggest you to use type L CFLs. They are largely used in veg chambers (veg propagators use them), usually in a setup of 2 of 55w (9600lm). The only change suggested to use it in veg is change the bulb colors, and you can wait the time for they last to change it. You can use 830 color in veg without problem, specially if working with clones. For a setup of 2 55w L CFLs, a axial fan of 80CFM is enough (there are some in the page the image reaper linked). I prefer 12V DC fans because they are easily dimmed and saves watts. Another fan/s between lights and canopy heps alot, moving the air into the chamber and allowing to put lights nearest.

If you are going to use CFLs, dont forget to put them reflectors.

I have a setup with 4 DULUX L 55w, in flower. 19200lm in 5sq ft. 222 watts of consumed power. I grow sog style with them, with very good results. For extraction i use 2 12VDC fans of 80CFM each, one working 24/7 dimmed and the other only with lights on. I yield about 80-90gr of dried buds each 2 months.