I see Minelab have just re-released the 4500 in the USA and it's coming here soon. Fitted with a CT Elite Mono I believe and cost somewhere around $3500.00 ???.
I've found heaps with mine here in WA over the years. I still have one and a 5000 and an SDC, plus a Whites GMT. My wife uses the 4500 to great effect with a small CT Platypus coil - basically a Sadie but with a solid core.
I did have a 7000 until yesterday,,,,,,,,,,sold it.