If you are looking for a lightweight one person tent but want a generous amount of space then the Big Agnes Copper Spur UL1 is an ideal choice. One of the areas where lightweight tents usually save weight is by having a modest vestibule. This is a compromise many lightweight backpackers are happy to make. The Copper Spur is deal if you want more room.
The Copper Super UL1 has a sizable 10 sq ft side entry vestibule that offers plenty room for storage and cooking. It manages to achieve this with only a modest weight penalty.
The Copper Spur UL1 only weights 5 oz more the than the ultralight Seedhouse SL1 which shows what a good job Big Agnes have done on keeping the weight down.