Been trawling the interwebs myself lately. Two man with gear is really 3 man territory.
Have looked at some of the ultralight weight ones and it seems they are either made of cling film, or with the American ones especially, the inners are made from a pair of fishnet stockings and pricy – Mutha Hubba HP, go-lite shangri-la, northface rock 3.
Robens are worth a look for quality at simplyhike, and i did find a roomy light one called Coleman Novae – 1.8 2 man or 2.3kg 3 man.
But I’m coming round to the idea you need two, a solo one < 2kg tent and 3 man up to 3.5kg which you share carrying.
Prefer dome types, top of my list at the moment for an all rounder is the Terratrio 3p – 2.8kg although not really a dome. Vaude have a few lighter ones too.
http://www.ubergear.co.uk/vaude-terratrio-3p.html
Am am also going to take a look at a Vango Mirage 300 at go-outdoors, 4m2 but a bit hefty at 3.6kgs.