ok a bit of a rundown of whats out there in Cromo hardtails,
DMR - everyone knows they are good, solid, options for horizontal dropouts.
.243 - 7.5 pound hardtail frame? if you wanna lug that around all day they are really nice, shortish TT, very BMX like
PX bomber - really sweet jump bike but a little small for any trail type riding, dead sexy.
Snipes - you'd be doing well to get one in australia.
KHS ridge one - no frills but good value hardtail frame
Surly - more of a tough trail bike that a jump drop bike, solid frames, i think you can get them through dirt works so any warranty issues should be easy
but in my humble opinion
Endless lifetime is the god of all jumping/urban/trail/burly hardtails, if i had alot of cash to blow in a rare imorted hardtail thats where my money would go.
http://www.endlessbikes.com
but yeah there are heaps of good al frames too, Planet X, Evil, 24/le toy. support the small companys, they're in it for the love of riding, not the cash.