Interesting - I reckon stripping and either blackening or much-more-lightly respraying those connecting rods will be the first task.
Now.... if anyone is actually disassembling one of these completely at any stage - is there any chance of seeing a photo of the chassis laid out below the body on a grid, to get an idea of the size/clearances of chassis against original body? There's an itchy little part of me that wonders how much work would be involved in turning the whole loco into a squat little freelance 0-4-0.... Firebox right forward, safety valves/whistle popping through the saddle tank that's hard against the shortened cab....
...forgive my sins against Photoshop MS Paint... I think the cab/back-end overhang wants to be a little longer in reality. I just really like lil' locos!!
- I should add, noticing that first and second axles are geared together was a big part of the inspiration... Should go without saying, I'm not afraid to get my razor saw blade dirty...