I think it is an excellant idea. It, no doubt, weighs 500+ less than most riders out there and shouldn't be too hard to service. It looks like there aren't very many non-factory parts on it and he probably used off the shelf linkages for the steering.
Brendan, it looks like you change the height just like you would on any other Scag walkbehind. Spacers on the caster shafts.