alexy wrote:
....
Ask yourself (then answer realistically) how important the movability
of shelves is. Most are never moved, once set up to the owner's
liking. If that is the case, work with the side pins until you have
the shelves spaced like you want them, then attach cleats to the back
and sides under each shelf, and attach the shelves to the cleats.

Actually, your idea suggests to me that if the shelves are to be heavily
loaded, the visibility of support pin holes in the back may not be such
a big issue, particularly if only the ones very close to the actual
height are drilled out instead of all possible. Then, a ledger strip
could be made which fit into those holes which would add quite a bit of
rigidity...