Actually, there's not all that much modification to be made.
I took my own Indigo v1 apart today (for assessing the maintenance required for a couple of wonky pots that need replacing)...
* Took the keybed out:
Pic1
* When tilted, you can already see the outline of the "TT":
Pic2
* Just a case of taking off the end-cheeks and the main chassis:
Pic3
* Voila:
Pic4
The real mod would then just need a smaller chassis to fit the unit on to, and new end-cheeks.