Dear Cindy

If you have or know of one near you ask the guys who mount museum specimens
to make some . Our museum tech makes them to the size we want using perspex
sheets. Our normal ones hold 30 slides and we have some smaller and a couple
larger.
They are quite deep so that excess washing buffers are not a problem.

Sorry for the tatdiness of this reply, but have had restricted access due to
mother-in -law using room that my PC is in.

Hope this is helpful

John Auld
Immunocytochemistry
Royal Free Hospital
London
UK