X-Particles never ceases to amaze me, it is such a versatile tool. Although not designed specifically to deal with cloth and soft body simulations, X-Particles 3 does a good job with minimal setup.
Add the XParticles xpConstraints object—which will tie your particles together—then combine this with the xpDeformer object to manipulate your geometry. You can easily create basic cloth simulation, jelly typography and all manner of wobbly things.
This tutorial shows you a few ways of setting up this kind of boingy behaviour with X-Particles 3.