Materials:
- PVC to NPT adapter (2" inner diameter)
- 2" flat washer
- 8mm nut
- 2" hole cover (for desks / countertops)
- 7 ounce kid's cup.
And not shown above:
- 1" brush w/wooden handle
- 1" angle bracket w/small machine screw
- Sticky-back velcro or ordinary electrical tape.
Modification Steps:
Below is the brush assembly. I found it was a tight fit with a 1" brush, but I didn't see any 3/4" brushes (1/2" is too small). It's at a slight angle to compensate. This picture shows the doser without the adjustable sweep vane in place. I folded over strips of electrical tape halfway lengthwise and attached them to every other vane, extending them about 1/8" inch.
Now the PVC adapter piece, washer, 8mm nut, and cover are in place. Since there is a small raised bevel on the top of the sweep vane, I had to trim a little from the inner edge of the hole in the PVC adapter with a utility knife. With the washer and nut in place, it sits nicely on-center and doesn't budge.
NB: I would have reused the stock nut, but it was too tall to allow the 2" hole cover to fit.
The finished modification. A few grounds might stick to the cup so I remove it and toss it in the dishwasher once a week, then choose another. This also give me the chance to pick a color based on my mood.

There's a lot less space with the cup in place, so you can't grind 4-6 shots at a whack. With the cup removed, the grinds shoot over the top of the PVC adapter. I rarely use this option, but it is nice to clean up by just popping in a new cup.
For sake of completeness, my rendition of Teme's sweep mod:
Quite simply attach the tape / velcro to the upper part of the vane (the one that moves up and down). With these two modifications and a quick swish of the exit chute, you'll recover nearly all the coffee grounds.