Hi LC, Years ago I followed Norman Fosback's newsletter called Mutual Fund Forecaster (now defunct). It also used similar data about net inflows and outflows from mutual funds along with the fund's reported cash reserves. It was very interesting.
Usually mutual funds have the heaviest cash reserves right around the market bottoms and have the least cash on hand right near market tops. With a little skull sweat it could probably be made to be complementary to the Idiot Wave.
I don't subscribe to "Trim Tabs" either. Just check their site once in a while for such info.