Luxe tents are light & cheap and seem to me fairly good quality (have no personal experience with them tho). If you haven't done so already, you can usually eye-ball several of them at Mountain Creek shop in Hobart.
Depends a bit too on your upper limits for 'cheap' and for 'light' ... what are they?
Looking 2nd hand could be the go too.
Come to think of it ... we've got a MSR Hubba Hubba in our tent collection that we haven't been using much recently ... bought ~2 years ago for South Coast Track (as answer to the question 'what is the most effective thing we can do to reduce our pack weight' for that 9 day trip) ... tent did very well, that was a good choice (there should be a pic or 2 of it at
http://ahack.org - Photos / Bushwalking / South Coast Trip) ... light, top quality ... would consider selling it for $250 if anyone was interested.

a.