I'm working on a replacement controller for the CubePro. While I do plan to sell these, the code will be open source (Marlin) and I'll release the board design files at some point. Currently I'm still in the design phase, but things are going really well.

Using a Teensy 3.6 as the base, I have Marlin 2.0 running with almost all of the original components.
All original wiring is being used, and all the connectors will be in mostly the same spots as on the original board.
Through Marlin I have the endstops, steppers, extruder heaters, extruder thermistors, and LED lights.

Now for the interesting parts. Most of this is tested through small programs, so I'll still need to integrate it with Marlin.

I have the built in temp sensor board working, as well as the AC relay board that runs the heater.

I ran a test program for the LCD and resistive touch panel, I don't know how Marlin handles a color LCD and a touch interface, but I'll cross that bridge later. I'll use a rotary encoder for now.

Next I have the two encoders (per extruder) working, same with the filament sensor but only when connected directly to the Teensy. The original setup is for the filament sensor board (including the encoders) to go to a PCB behind the extruders. This board seems to handle the filament sensors, encoders sensors, extruder fans, and part cooling fans. Theres a 9 wire cable going back to the control board, but I haven't looked into what is being transmitted. There's a PIC16F on the board, and if I can't figure out how to control it, I can always write a replacement firmware for it. Worst case scenario is I make a second PCB and replace the extruder PCB entirely. For my testing right now I won't need the sensors, and I can just wire the fans myself.

I'm using TMC2208 stepper controllers, being controlled via UART from Marlin. The connectors are 2.0mm spacing, so I soldered them to the surface of the pads and superglued the connector on the edge of the PCB. If you can see under the stepper board, there's the two large fans that are always running. I plan to have a cutout for the finished board to utilize these fans to cool the stepper controllers. For now I'll use a fan blowing horizontally, with heatsinks on the top and bottom of each controller.