Are there any hostel-type places out there that will let you rent a bunk or a room on a night-to-night basis for bitcoins (particularly in the US)? Due to max occupancy and other regulations, there seems to be precious few hostels in the US, and I really enjoyed them while traveling.
I don't know of any hostels accepting bitcoins.
What I do know is that there are a LOT of hostels in the US, but very few of them are part of Hostelling International. Most are independent or members of smaller networks. For instance, hostels.com lists 14 hostels in Washington DC, only one of which is HI member. Many hostels cater to a specific local audience. For instance when I was hiking the Appalachian Trail I stayed in a number of hostels near the Trail which catered only to A.T. hikers and rarely if ever saw anyone else.