I run a F series mower in the summer as well. I've seen snow blowers, rotary brooms, and blades, but I have never seen a tiller. I suppose the main reason is, you would have to back up while using it or you would be driving over your freshly tilled ground and packing in all down again.
As far as rigging up some home made tiller, it would be tough to do since the pto rpm on the F series is approx. 2500 rpm instead of 540.