Similar to you Leshy, I can't sleep in a mummy sleeping bag so I bought two snugpak jungle bags (Right and left hand) and they zip together for a double sleeping bag for summer use, plenty warm enough and plenty of space, was very happy this summer in my hammock.
I haven't been out in winter yet but I'm planning on supplementing it with a snugpak underquilt, a snugpak jungle quilt, and a wool blanket.
I have been using the snugpak jungle blanket as a duvet at the moment and it is plenty warm for me surprisingly warm for it's weight and bulk.
But then I sleep warm and don't tend to hike with my gear very far.
I also got one of TwoDogs Brit wool bush shirts which I'm planning on sleeping in if it gets cold, as it really is too warm to do any walking/work in, but then I always get too warm rather than too cold.