I'm talking about a scooter for people who have difficulty walking. i don't know if this is exactly what you're looking for but at least you can start to check there: http://it.wrs.yahoo.com/_ylt=A0geune06jt...
http://it.wrs.yahoo.com/_ylt=A0geune06jt...
http://it.wrs.yahoo.com/_ylt=A0geune06jt...
the firsts two links are in english as well. in the third are shown some prices and there's a map of the location
terrenzio offers motion transport even for disable people : http://www.terrenzio.it/ (the link it's in italian but there's an e-mail address so that they may help you with some more infos). iI looked this up for you in the yellow pages, but couldn't find a place that rents scooters, only electric wheel chairs. However, here are a few numbers and addresses of the bigger places:
Laboratorio Ortopedico Sanitaria Europa - Via dei Georgofili 143 - tel. +39 065123297, 0651230001, 0651604342
Sanital - Via Magazzini Generali 4/a - tel. 065782503
or
Vai Pellegrino Matteucci 32 - tel. 0657301296
Italo American Ortopedic (they probably speak English here)
Via Cividale del Fruili 3 - tel. 067017788, 067010769 - e-mail italortopedia@tiscali.it - site at: www.paginegialle.it/italoamerican
Good luck and hope you enjoy Rome! | 