There are numerous sites on-line for the hardware kits, most come with instructions for building your own. The kits range from about $250 to $400, depending on the lifting system (and who's selling). Lumber is additional. All things considered, I would recommend buying the parts rather than playing with diy engineering.

Yes, you can use ready-made bookcases, but keep in mind that even unfinished ones are not inexpensive. You can also add your own doors to bookcases, to turn them into partial or total cabinets.

The cases to either side of the bed should be slightly deeper than the folded bed, usually 12" to 15". I do recommend that they be attached to wall studs.

The concealing cases can be any depth, but 9" to 12" will look good. I find a tracked sliding system easiest, and on one, I did add concealed roller casters because of the deep carpet. Yes, the casters do make it easier to move the cases. I also helped a friend make one, using panels instead of cases for the concealment. The advantage is a slight gain in floor space while the bed is concealed, and the disadvantage is the loss of the shelf space from using panels instead of cases.

If you were to fill a 12" deep, 3'x 7' case with books, the total weight could easily be in excess of 500 lbs. The fewer books and art objets, the less weight, but even empty cases can be quite heavy. A double-sized mattress with spring will weigh less than 200 lbs, plus the moving assembly. We are not talking something you can pick up with one hand, so care must be taken to follow all directions carefully. Once assembled, the bed is indeed easily raised and lowered (two hands but little stress, lol).

I assume that you want to build it yourself to save $$. But just in case, here's a link to one ready made. Others show up on "library bed" search.

Here is a link that might be useful: Library Bed

saw that site last night and it does have some specs for dimensions of their system which might help a carpenter with materials and design but not very easy to read/use...

my husband would not be DIY this project unless we could figure out how to use pre-built bookcases and even then I think we would be afraid the bed would snap up in the middle of the night with someone in it...

we would get someone to do it for us..have a friend who builds smaller commercial properties and some pretty expensive homes -- he knows trim carpenters who do beautiful work--if they only had to add some trim to prebuilt units and install the murphy bed then it might be pretty reasonable...if my husband did it no wood cuts would be straight and he might lose a fingertip...
cheaper to pay professional if it has to be built from scratch...

Have you considered how inconvenient it's going to be to take everything off the shelving when you want to use the bed? And where you're going to put the stuff while the bed is being used? And if you only plan on using it infequently wouldn't you want the bedding to be fresh?

IMHO it is an impractical ideal.

Neesie--if you looked at the photo link you would see there is nothing to remove from shelves----the bookcases that conceal the fold-down bed frame SLIDE/ROLL to the side--everything on shelves stays in place--if needed there could be a molding trim a little wider than the thickness of the shelf added to the front edge to ensure nothing slides off...
that is why this is so functional--

neesie ~ You don't remove anything from the shelves. The cases which conceal the bed are slid to either side. You do have to be careful that the slide is *smooth*. If one is going to put delicate art objects on the moving cases, then the use of museum wax/putty would ensure no tipping over.

People who have murphy beds, like them because the bed and linens can be put out of sight, as well as having the available floor space. This is especially convenient when one need a bed only for the occasional guest; the room can otherwise be used for a study, library, etc. The beds get no more musty than any other bed, and imo stay fresher because dust does not collect on the springs or underneath. One would, of course, put bedding on fresh for the occasional guest, or change as usual if the bed is in daily use.

My neighbor has that exact bed. It works well for her. There was no architectural changes. It just occupies the wall between two doors in what ordinarily is a study.