Building a Murphy Bed/ Bookcase

So I'm a new homeowner-to-be, and having lots of crazy ideas... (33 years' worth of "when I own a house, I'll...", I guess.)

It's a great house, I love it, but one problem is the guest room. There is not an obvious place for it, but we do want to make visitors welcome, so I plan to use the family room/ sun room as a playroom, office/ studio for me, and guest room as well. :-/ It's a big room with a full bathroom right off of it, and I think it's achievable. The main sticking points in terms of what we have now vs. what we need are a guest bed and toy/ art supply storage.

I checked out sofa beds at Ikea and the sofa part was fine but the bed part sucked. Foam mattresses through which you could feel the bed support. I want to have something comfortable enough for E.G.'s 80-something grandma (who is so great... but I digress.)

So, once I started thinking about a comfortable mattress, that led me pretty quickly to the idea of having a Murphy bed. Then I decided what would be REALLY cool is if the bed could have a surround of deep bookshelves (2 feet) and then have shelves on the underside of the bed (~1 foot, allowing 1 foot for the mattress). Something like this:



This is approximately where it would be in the room:



So, I've never done anything remotely like this before, and while I really like the idea -- it would solve several problems -- I have no idea of expense, difficulty (how would I get the bed to swivel up and down, stay in place, etc.?) or general feasibility. So any advice would be appreciated. (Nothing at all definite about whether we'd do this, and would probably be a while yet if we did, but just curious.)

Thanks!