There’s a lot of choices for bivvy bags and one-man ultralight tents. With these you do have the condensation issues, the often garish colours (fine for Mountaineering of course), and the delicate materials than can easily get snagged or get spark holes and tend to flap around in the wind, but there are still some nice designs around. This one from Marmot is quite a clever design, although the day-glo colour is not for me, but looks like some real thought has gone in to it: