I know CX is popular in Europe, but everyone in this region thinks I'm crazy taking a road bike in the bush.

I've never had the chance to look at a real CX bike, but what makes a CX bike?

I use this beast currently (usually after training with friends on road).

A CX bike has more clearence for mud and bigger tires and has brakebosses for V-brakes. Also the geometry is a bit different. You have a higher bb and a longer rear for more stability. These are the biggest differences with a normal roadbike, but ofcourse there are more, check www.ridley-bikes.com for a bit more info.
www.cyclocrossworld.com is also a nice site to check out, they have a lot of the little 'gadgets' that make a good crossbike, but this forum should be able to give you some advise as well
Are you looking to convert your current bike to a cyclocrosser?

The Appolo 1 has a compliant steel frame and the wheels are fairly comfortable.

The tracks around here are fairly hilly so I'll be keeping the gears. (If we raced I'd consider moving to STI).

It's got 165 cranks so it has reasonable clearance.

Next set of "borrowed" tyres could well be chunky for CX use.

That thing's gotta weigh a ton and a half. Sucks for carrying.

At least ditch the "fenders", spoke "protector", and reflectors.

I'd make it a 2:1 geared single-speed. At least it cuts weight enough where you could use it. Since it's steel, you could have canti mounts brazed onto the frame. Those are best for mud clearence. Most cross bikes are geared with 39-42/45 gearing and a wide road range cassette in the rear, slightly more upright position, and wider bars.

There's a fair amount of frame diff's too, but that'll work for cas use.

It's probably a good thing you can't see the bike stand on the other side.

It does weight 1 1/2 ton, but there are no CX races in Australia, so I'm in no rush.

Canti brakes, knobbie tyres, gearing changes... what else would make it a better CX bike?