I'm not sure that I've ever seen a front mounted yard sweeper - either for a 3320 (or my 3520) or any other tractor. Do you know for sure that they exist?
I have a 48" pull behind sweeper (not sure of the brand - might be a Craftsman) that I bought very used for $50. I use it a few times in the spring when the grass in certain parts of the yard grows faster than I can get to mowing it. I end up hooking this thing to the drawbar of the 3520 and dragging it around the yard. Luckily, our yard is pretty private so none of the neighbors see how ridiculous it looks with that big tractor dragging that little sweeper around. :laugh:
I've often thought that it would be pretty cool to mount a sweeper on my FEL. But my "in my head fabrication skills" are MUCH better than my "actually do it fabrication skills" so it ain't happened! :laugh:
Post up if you find something front mounted. I'm not sure if it's something I'd spend money on but I would be interested in seeing it.