I don't know if you will be happy trying to use the Little Su with a harness. It looks like the power button is in the base, and so if you have the dildo/harness positioned right it will probably switch on and off as you thrust
You might be able to get a bullet to stay in the Joque or Theo (don't have one so I can't say for sure) and then use a second dildo (using the Aslan Double-Up Cuff or similar) for the filling feeling. Alternatively you could try a double - the Nexus Maximus (hard to get a hold of right now) and Tango (liekwise
) provide clitoral stimulation and include a vibe - too bad the Share doesn't as it's a pretty good design as well. I have heard that it does provide a decent amount of clit stim from the thrusting motions if you're still interested in going that route.