not even a clue what kind of cfm one of these pulls, but it's gotta be fairly significant if it is enough to blow air to an entire house through the central AC. the blower itself is about 2ft square by about 10" depth...although it's in a housing closer to 3.5ft x 2.5ft x 2ft.
Would one of these big blowers suffice as a DC with proper modification (perhaps on top of one of Phil's wonderful can lids)?
No, those won't work. They just can't handle the resistance of 4" to 6" ductwork. They are intended for larger ducts like home ventilation systems have.
They will, however make awesome air cleaners! Build a plywood box, insert furnace filters into one end, outlet the blower on the other, and you're good. I'm always keeping an eye out for them on CL just in case.
I think that I have a simple plan for an air cleaner - I know I built one !!
Send me a PM if interested