If you are reasonably handy and find the idea of building from scratch even remotely appealing, that is the best way to go.
I'm close to finishing my first upright, and I'm having even more fun than I thought I would.
Here are some advantages:
You don't ruin a classic (that Robotron could be restored).
You get to build exactly the cabinet that you have in your mind's eye.
You will learn new skills.
Pride of ownership - no conversion or pre-made cab will be remotely as satisfying as one you built yourself.
I'm sure there are many more advantages that others might chime in with.
This forum contains all the information you will need, and if you need help or suggestions, all you have to do is ask.