I mounted the HF 12" bucket that Kevin pointed out, and used it to dig two drainage ditches today -- sorry, no pics, I got rained out....
First, regarding mounting. My local Tractor Supply had a 3/4" ID bushing in one of the HW parts trays that I cut off pieces to bush out the large hole where the dump-cylinder mechanism attaches. Also bought a stock of 3/4" ID washers to use for shims. Used one per side, per bolt, to shim the narrower PT mechanism to fit the wider HF spacing.
Also bought the only 3/4-8"- 10 thread bolt that the Tractor Supply had and used it to mount the bucket dump arm. The stock 6" x 3/4 bolts on the PT aren't quite long enough for the bolt to completely come through all the threads on a NyLock nut. Because the bucket dump mechanism is safely hidden behind the bucket, I simply used double nuts on 8" bolt to lock it in place, and left the remaining threads exposed -- also used flat washers under the bolt head and the double-nuts. Now, I need to find another 3/4x8"x10 bolt for the bucket hinge point, add a fresh NyLock nut, and cut off the excess...
Because of the different spacing of the mounting holes, the bucket does not extend (uncurl) quite as far as the 9" PT bucket -- you can't quite put it flat on the ground. Similarly, the bucket curl/dump cylinder does not completely retract before the center tooth hits the 4" square beam/tube of the minihoe. Doesn't really impact its use, IMO, but it is something you may want to be aware of... it was made for a machine with slightly different geometry.
Now to my impressions after use: This thing digs real well -- but it is at the limit of the PT's minihoe stock bucket curl/dump cylinder in breakout force, when in hard clay with slate/shale rocks. There were a few times that I had to use the treadle to move the PT slightly in order to get the bucket to curl and take a full bite... I was never unable to get a full bite, and I adjusted to this need quickly.
In softer soils it works fine. If your goal is to excavate and move a volume of dirt, it must dig at least twice as fast -- if not faster -- as the 9" bucket, because the bucket is SO much bigger. I also found that it cleans out the bucket MUCH better in muddy, sticky, mucky stuff -- the wider bucket and the larger volume makes the "bite" of muck much easier to jar out of the bucket. I was digging some in black sediment that the locals call "crawdab mud" -- sticky, mucky clay kind of stuff -- and I never had to stop and manually clean the bucket. I could always jar the glob of goop out of it....
My first impressions are VERY positive overall, and a great addition to the toolkit! Thanks for the tip on the deal -- Kevin! Sure can't beat the price and $6.99 FedEx shipping all the way from California...
Another observation -- for those of you running stock wheel track -- this thing doesn't leave as much space to articulate the front wheels to empty the bucket as the 9" bucket does. Just be aware, and clean up your trench as you go, so you don't need to go back and straddle it to clean it up. Part of one sidewall caved in on me, on one trench where it was really muddy/mucky, and I had to do just that. I was glad to have the wider stance of my modified wheelmotor-machine...