A lot of mountaineering gear has been as light as it could practically be for a long time. A lot of mountaineers use shelters and sleeping bags and sleeping bags from the cottage industries that the UL backpackers use.
The other pack makers worth mentioning are mchalepacks.com and wildthingsgear.com. Wild Things also makes some very good clothing. Packs that work well for climbing-ish things are different from packs that work well for backpacking, at least in most people's opinions.
I think there is a company named Beyond Fleece that custom makes some good clothes.
Pick up a coply of "Extreme Alpinism" by Mark Twight. Although this book is getting a bit old, it does lay out the way to think about traveling light on technical ground.