Absolutely I've heard of Mad Hatter potato chips. They were my favourite by far and I consumed copeous quantities as a child growing up in Toronto back in the sixties.
Unfortunately I do not have nor have I been able to locate any old bags or advertising. I do however have some very keen memories which I hope will be of some interest to you.
The package itself as I remember was predominately red with blue and white trim and centered on the front was the Mad Hatter character with the trademark hat and card which displayed the 10 cent price. Interestingly, but not surprisingly, special bags were used at Exhibition Stadium, and I'm sure at many other rip the consumer off events, which had blank cards in the Mad Hatter's hat so they could charge 15 cents.
There was five different varieties available each indvidually distinguishable by a coloured horizontal bar at the lower section of the bag. Regular(blue w/white letters), Rippled(same as regular with the word "rippled" in wavy fonts), BBQ(yellow w/red letters), Bacon & Hicory(orange w/can't remember letter colour), and Onion & Garlic(green w/black letters).
Mad Hatter chips were around until at least 1969 and I had always thought that they were bought out by Hostess which came on the scene about the same time although I'm quite certain both were available for at least a couple of years.
Prior to Hostess, I only remember Sherrif(terrible chips), Humpty Dumpty, Lays and of course Mad Hatter. Hostess sure were innovative as far as new flavours but my favourite, simulated Hot Dog in 1971, was only around for a couple or three years.
Anyway I'm glad to know that I'm not alone in missing Mad Hatter potato chips and please keep me apprised of any memorabillia type finds or information.