EDIT: Sorry, didn't realise he'd already posted it! Duh.
3D Object Converter now has the ability to import .tgo format, which I thought would be of interest (must be a first?).
http://web.axelero.hu/karpo/
http://web.axelero.hu/karpo/develop.html
No export to .tgo format however, and Zoltan tells me he has no plans to do so.
Thanks for the info about this!