You want to be careful what you say about the F250.
In the US, the F250 has two body types - it has an F150 body type for the lower spec model with uprated suspension and greater load carrying capability than the F150. The F250 Super Duty is based on the F350 chassis but is shorter and doesn't have the huge MoFo suspension. From the front, the F250 Super Duty and F350 look the same. The Excursion is based on the F250/F350 shared platform, yes. The Expedition is based on the F150 Platform. It's only the F250 Super Duty that Australia is getting. I filmed a RHD F250 with a Turbo 4.2 Litre Diesel 6 - and you can find it here: Aussie Mustang and F250 Film
It's the Expedition that I'd like to see in Australia. The Expedition makes the Land Cruiser look like a Medium Size car, and the Excursion makes it look even smaller. Maybe in a few years time it might be worth while bringing over an Expedition, and fitting the RHD running gear from a Brazil/Aussie RHD F250 into it. Or better still, bring over a Lincoln Navigator, Now THAT would be plush - even in 5 years time! Although Aussie RHD F250's don't get the wood-grained dash....
I don't know if Ford Oz will be bringing in the Excursions, but it'd sure be fun wouldn't it. The Chevy Suburban gets here. I think the Expedition stands a reasonable chance in Oz if they can demonstrate good offroad ability and have a hald decent Diesel.