A telephone switchboard is tough to find, unless a nearby
theatre has recently done the musical
Bells Are Ringing. Being a lighting guy, I'd have to suggest looking for a "telephone-style" lighting
patch panel. But they're usually huge, and contain lots of scrap copper wiring.
Just a thought: Get a bunch of wooden sewing thread spools. Glue a 1/4" dowel onto them. Attach a 14/2 black cable on the other end. Drill a bunch of holes in 3/4" plywood in which to insert the plugs. Add a rotary dial and an old-style operator's headset. Any surplus electronics stores in your area?
Here's more or less what you're trying to create:
See
this, for the ultimate telephone switchboard operator. Just build something close.