Glass block windows can be really fun. We installed a pre-made one in our shower wall. It installed just like a regular window (i.e., has nailing fins, etc.) So you don't need any specialized contractors to assemble it.

Ours does not have a vent window. (It is unreachable, anyway.) But if you google around a bit, you can find some vendors who offer them.

Here is a link that might be useful: One source of pre-made glass block windows.