Sarah, I know this is not what your after, but I did see a V8 100 series Landcruiser "compete" in a Dutton Rally a few years back, maybe 5.
I have seen a few nice Foz's about, and if your not really going into rough stuff, outback (Canning Stock Route) you could make it happen, especially if your with a 4WD that has a good low range gearbox, and travelling with friends is a good way to 4WD.
Suspension lifts can help a 4WD, (and do) but the tyres are more important in my book. So smaller rims with 60+ profile tyres for off road. This will increase the length of the tyres footprint and get you out of many places when you drop tyre pressures. See these guys
http://www.subaru4wdclubwa.asn.au for what a Foz can do, eg the powerline track (photos there on photo page). You won't be able to do what my 105 Landcruiser can do, but you'll have fun anyway.
If you can, go with a turbo charged Foz, throw some coil overs on, This will make it easy to change your ride heigh, see the page Mao has on this forum with a Honda Civic Wagon on an Anti-lag night at Barbs, Windem up to get a couple of extra inches in ride height, soften the shocks, swap over the rims/tyres, while your doing the suspension, and off you go to the bush/beach, change to a set of semi slicks on another set of rims, lower the ride height, harden the shocks and your ready for Collie or Barbs. (Nice 4WDing down here as well)
Here is an eg, but its not in WA
1999 SUBARU FORESTER GT AWD 79V MY99 Cars For Sale in NSW - carsales.com.au - carsales.com.au
This may not be perfect, but possibly the best compromise this side of a Porsche Cayenne, VW Touareg, or a BMW X5.
If you can convince Mark to let you drive his car, then look at a Pathfinder.
Tim