The other day I got hold of a Tait TB7100 1U repeater. I thought I might make a good basis for a MMDVM HotSpot or even repeater. Apparently the RX had a sort of a problem. Using the service manual I discovered that the TCXO for the RX was missing its power supply due to a removed resistor. After fitting in a replacement the unit worked ok with a testing configuration for a FM repeater.
So that would make a good hardware for a MMDVM HotSpot now. Some research on the Yahoo group revealed that you need to directly wire RX and TX audio directly to the two modules on the inside.