Donald,
I agree with Ian, we build them as cabinets so you can change length, width, height, anything, then add them as a batch item to the job.
We rarely build one unless there is some oddball size or something. There are too many parts and are tedious to build in the shop so we found out it was best to order the spice shelf, mark it up and stick it in the cabinet. The shop made pullouts really don't seem make you any money.
Here is a look at what we build. I have the CNC cut pockets underneath the adjustable shelves to drop over a spoon type shelf pin so the shelves don't slide around.