Here is an original design that I have been working on for some time. It's a combined vibrato and a stutter effect with minimum controls. I'm very happy with the results and I hope you like it. :)
The idea is simple: the signal is split into two paths that are out of phase. One side is goes though a highpass filter (that cuts eveything below about 500hz) and amplitude modulation, then both signals are summed back together. As the two signalpaths partly cancel out from 500hz and up, this creates an interesting phasey sound in the crossover frequencies - a vibrato'ish sound that is a bit different from your standard tremolo.
The stutter mode was added later as an afterthought. The way I set up the VCR (the JFET acting as a voltage controlled resistor) results in a very agressive amplitude modulation, so I wanted to take advantage of that in the design.