I think you have many options available for your situation. You can do any of the following:
1. Figure out what parts are broken on Litejet and buy replacements from ebay
2. Replace 11 years old system with a newer one like Elegance, Omni-bus, C-bus or Loxone. The new Elegance comes with mechanical relays backup that will allow you to wire switches directly to the relays in case of MCP failure. Omni-bus and Loxone modules have a smaller footprint that may fit in your existing can.
3. Replace Litejet can with array of 6-gang electrical boxes and install wireless switches with z-wave or insteon tech. Wire your low-voltage switches to Elk zones and make it control the switches based on zone status.
4. Replace Litejet relays with electromagnetic power relays, low voltage switches with regular switches and control the loads the same way as any "standard" wiring would.
I have a romex run to one keypad in every room to allow for the "dumb" operation during service on the system, have not had to use it yet, and the system has been working for a decade without any replacements needed. I have 96 loads, 8 fans, 300+ control buttons and I would never trade this for a "wireless" solution. Considering that I had to replace my z-wave switches every 2 years, it would be quite a chore had I opted for that technology.