I have planned on doing something similar to what Rick is talking about. I'll have to lookup the accusump. I had planned on using one of the differential cooling pumps and a couple check valves (to prevent backflow through either the engine pump or the preoiler pump).
I've seen the pressureized bottles but it seems like a PIA to have to cut the valve off before shutdown. I don't expect to see G forces that high that the pan baffle can't handle either.
The diff cooler pump seems like a good choice since it's built to run very thick gear lube through it. I believe the pump was about $200. Cheap insurance.
Here's the pump:
http://64.202.180.37/files/pump.pdf $185