lfnle,
I have a YM1301D - a Yanmar gray market tractor. It is similar in size and HP to a made for US Yanmar YM169D. I have mounted a Yanmar YMM-45 belly mower on it that is run by an electric clutch on the front of the engine. You can see pictures of my tractor on <A target="_blank" HREF=http://www.geocities.com/gregbirkymustang> my web page</A>.
This mower was original equipment on made for US Yanmars YM135, YM155, and YM155D. The front pto does interfer with the loader which came on the tractor, but I'm in the process of relocating the electric clutch under the battery inside the hood. This kind of stuff takes some ingenuity, but I live for that kind of stuff.
I did have trouble this fall with the rice tires tearing up my lawn after the fall rains started. But I have a set of Michelin 265/75R16 tires that will go right on the rims I have, and should minimize this problem. The fronts don't tend to tear up the ground as much as the rears. I wouldn't want anything but the rice tires for moving snow - which I do with a cheap garden tractor snow plow which I mounted to my 1301D.
If you aren't a tinkerer, and willing to do stuff yourself, and you don't have a full service dealer nearby who will take care of problems for you, then maybe a gray market tractor is not for you.
I attached a photo here of my tractor with the belly mower on it.