Thanks for the responses. I have a tough time visualizing these
things, but it seemed to me that 4' would be too small for a true
walk-in, but the U-shaed shelves are likely a good idea. I'm thinking
I might use the basket-type wire shelves in order to improve light and
make it a bit easier to clean.
I'll likely avoid any expensive hardward like heavy-duty sliders; part
of the reason to build it this way is to save money versus custom
cabinetry - I'm handy enough to put up a few walls, drywall them, and
hang a door, but not up to doing my own cabinet-making.
I might also hit a few show-homes to measure their pantries, and see if
a 4' one is worthwhile...