Wanabebwana, welcome to NitroExpress.
I agree that the only appropriate action for a classic big game safari rifle is the Mauser '98.
You might find that by sourcing a very clean FN action and adding the square bridge you may be right in genuine Oberndorf square bridge territory as far as money goes. Oberndorf actions are out there, just need to be patient and turn every stone you can think of. I too have a soft spot for square bridge actions but the standard round top action is the one Jeffery used for their early 404's (before the magnum actions became available).
In fact, if you plan on shaving the rear bridge as Jeffery did, you may want to stick with the regular round top action anyway.