ok.. I found some Yam Bean (chinese potato) at my local asian market (about 500m from my house believe it or not, after searching all over LOL)

I roasted some tonight, with lamb shanks and broccoli.

The verdict... a very nice potato substitute without the carbs. It has similar taste, similar texture at roast potato (but not so soft as overroasted gets). Its kind of crunchy like an apple.

VERY GOOD!!

I expect it would very easily work well as chips too. I am interested to try it mashed, expect it will work fine.