have you looked at the "drop in" surge boxes from either fuel safe or ATL? they have the features you want without having to engineer your own solution, or if you want to make your own, one of these companys offered one way check valves that that you could put into your surge box.

I have to admit, the option of using an OE fuel pump module is what I ended up going to after dealing with the same external fuel pump/baffled tank/return system issues for a few years and I am really happy with it. The one thing to consider is that if you are going to drive your car a lot, if something goes wrong, you have a really good chance to pick up a new OE fuel pump vs trying to find speed parts in the middle of nowhere - been there done that.