I see what Neil is saying about just a get it done job.
I am not sure that is what Neil is saying. What he said was "...you are moving into a different style of cabinetmaking". While it is possible to build the project out of solid wood I would question the benefits of doing so. To me (remember I am an architect who also builds stuff trying to make a living), I have no such bias to modern day materials (no hate mail please
I am a little confused by your description, so let me state what materials I would use and where I would use them.
3/4" plywood for all carcass construction (edged with solid wood, perhaps with detailing), depending on the construction the backs of the carcass could 3/4", 1/2" or 1/4" plywood.
1/2" solid wood drawer sides, 1/2" plywood bottoms for strength and stability. The thickness of the face of the drawer would depend on the design (ie whether dovetails are going to be used, etc).
The material for the construction of the bed would have to be based on the design. It's possible (but costly) to make it out of solid lumber but it probably would end up as some combination of plywood and solid. This will create a potential finishing problem, unless the project is to be painted.
Also he's talking about doing just 4 full sized drawers.
This sounds a bit nutty to me due to the size. Drawers that big will be unwieldy to use and I would advise you to talk to the client about making sure the drawers aren't so big that they are difficult to use.
Nonfriction tape and such can work (but it can also fail). You can also use traditional wood guides with wax, with the proper tolerances for wood movement waxed guides works very well and wax never comes unstuck and gums up the drawer movement.
Another thing to remember is to measure every
opening (doorway, van door, whatever) that the pieces will have to fit through to get it from your shop into the bedroom so you know what the smallest opening the pieces need to fit through.