[Yo-DUH_87]

Umm, no offence, but the pwr_good is on all the time, it is just a 5v ttl logic signal saying that "all is fine here now, thank you for asking."

Instead, why not power it from the PSU's 5v line? If you realy want to go that route.

I don't know, but IMO I think that purchacing the extra mosfets would be cheaper than getting all those relays.

Since87, the reasons the 2nd mosfet is there is a. the internal body diode, and b. to prevent reverse current while the gate is saturated.