Have you guys seen/heard of the Testarossa. Used by a lot of contractors in the South Island (NZ).
They have a fan above the blades which helps push clippings into the large plastic catcher they work well in the wet (some even use them in the rain). Normally buy the body (aprox $400) separately and bolt on what motor you want (little honda like GSV190 is most popular or suzuki two stroke). Down side plastic body last aprox 1year till it cracks or twists. Stone can blow hole thru sides and axels can break
here is the blurb.
"Testarossa mowers are the choice of professionals. Used by lawnmowing contracting all over New Zealand every day. Testarossa mowers are made in Italy by Global Garden Products (GGP) who are the largest outdoor power equipment manufacturers in Europe and produce the Castel Garden range of ride on mowers. Testarossa mowers are made with an ABS plastic chassis, very light weight and will leave a beutiful bowling green type finish on your lawn."