Tony, I bought and have used a RiData Pro 150x 8GB CF card and has worked great so far, only used it one show, and hopefully i never have to use the cf card over the HDD, hoping the HDD lasdts me another 3-4 years, easily replaceable HDD fix tho. anyway, these go for around 150 new/used. got mine used in mint condition for 150 FWIW
i also like being ablew to run just the CF card, bet it saves some power too, i know writing to BOTH the HDD/CF Card it def sucks some juice