Wall beds, aka Murphy beds.....need advice

Hi all,
I have a wall. That's good. It exists in my wife's work/client/office room. The issue is we need a place for a bed when quests or relatives visit. We have a good Ca king 6" latex mattress that would probably work quite well with a 6" to 8" box spring under it. The mattress is currently stored and not in use. I have recently been thinking of a wall bed in the previously mentioned room. There is one wall that it would work on, but only if it is the bed unit only.....no bookcases, shelving, etc. that would widen the footprint. Does anyone know of a quality but not absurdly expensive provider of such things? Also I would like that it could handle 12" to 14" bedding (per mattress/box spring dimensions above) and the final height of bed from floor would be about 23" or 24". Some bad memories of rolling out of some sofa beds about 12" off the ground. Any leads, links or opinions would be appreciated.
Regards,
John