It's funny you posted this because I just got the email and got very excited. I have no idea how much it costs or if it would help CFS but there have been good reports on VNS. It does say contraindicated for POTS so I don't know if it will be bad for me.
I think I've been doing something very similar with a TENS unit. It helps when food doesn't seem to move through my GI system. If it's patented, it might be possible to find the patent and figure out how to replicate it if the specific product isn't available to you.