I have made a mirrored version and was about to post my remix complete with remixed x-carriage, mounts, and bltouch bracket but just discovered the license on this doesn't permit derivatives .
If you have two titans you've purchased here is what you need to do with this as the model (I used tinker-cad but whatever CAD you are comfortable with should work:
1: Import the back and front of the titan model
2: Mirror them
3: There is a lip on both parts that fit together - you'll need to shave them a bit or you will have a lot of filing to get them to fit together
4: The front upper right (near tension screw) has an extended screw piece that fits into a hole on the back - you need to increase the diameter on the hole on the back
5: the holes on the front and back where the large gear slips into need to be increased a bit
6: On your second purchased titan (the one you are replacing) there is a very smal bearing on both the front and the back - carefully pry them out and put them in you enlarged holes on printed part
Thats it - it works and you can put your printed part face to face with one of your purchased titan's to get dual extruders without weird offsets.