I have got a Panasonic split inverter. Its the latest 7.5KW one....I guess I cant really help with the pricing thing because a mate of mine works at Harvey Norman so he sold it to me for cost price, literally 50% off the sticker.

Installation was about $900. If the units were installed back to back it would have been $500-$600 however the external unit ended up having to go further a long the wall which meant more plumbing and wiring.