Over the last couple of years, I've been using the MSR Zoid tents.

Without the footprint and sticks, you can roll the 2.0, 1.0 and mini down to loaf of bread size, and hang the poles on the outside of your back pack.
IIRC, the Zoid 2.0 weighs in at around 3 lbs. total, and it's a generous 2 man/3 season tent.

The Zoid does have some design flaws, but at the time, they were the lightest and smallest tents I could find.