i'd go zvex ring tone for small and good sounding.
i've never actually played one, but if size is an issue you can also look on youtube for the Copilot Android ring mod. you can make the tone judgments yourself.
with that said, i own the moog
John, I used EH Freq Analyzer since 70s, but it is not small. I eventually took it off bord (with tear in eye) and use fuzz with ring mod tone in it instead (Lovetone Beleive or Monsterpeice Angry Dick 2000 which you might like for Pygmy Love Cyrkus).
BTW, I really like your playing. Thank you for making the effort.
It's unbelievable that a decent ring mod in a small box is so hard to come by. Try the copilot- it's pretty decent. I use an alesis bitrman- not too big, but it has it's own issues, although it sounds great.
Oh- i forgot about the ringtone- with it's extra options, I forget it does a decent static ring mod as well. Pricey, of course. . .