Have you come across the Model 72 from Studio Technologies? http://www.studio-tech.com/product_m72.html
Yes, I was given a gift of one my Mr. Kapes, the designer and owner of Studio Technologies. It is the epitome of a great Audio only box. It has meters and a loop through wet comm side. Mr Kapes really has the corner on the best intercom interface equipment bar none. Here is the Model 72 listing at $245.00
The hybrids are astounding and have features that make them more than just a hybrid, like built in comm power supplies. My favorite is the Model 47 with 2 independent hybrids with power on both pins 2 and 3. Pair a couple of these with an RTS 1620 dialup and you have a terrific remote box.