[sdiy] LFO inertia

[anthony]

I'm working on a sort-of chorus in which I want to modulate the 'rate' LFO 
with another LFO (is there a chorus design, commercial or otherwise that 
does this? I mean it wouldn't take a genius to think of it or anything but I 
don't think I've ever seen it).

More and more I've found myself sweeping the rate control like it was a 
Leslie speaker speeding up or slowing down. What I want to do is have the 
control lag regardless of how fast the knob is turned (but with the 
aforementioned LFO off) - like a rotating cabinet would do. I thought about 
using a Vactrol-ish thing but those have a pretty fast attack relative to 
their decay. Which /would/ actually be like real life since I think a 
speaker spins up faster than it winds down, but would it be enough I wonder? 
I have some teeny incandescant bulbs. Might those work? Or am I overlooking 
a simple way to do it?