Have you considered winter (hard) squash? Some are drier than others, like Butternut or Buttercup.
I go sweet potato, coconut oil, cilantro, red pepper, yellow onion, spicy pork sausage with poached eggs on top...
"The problem with quoting someone on the Internet is, you never know if it's legit" - Abraham Lincoln
Anyway, I guess the best thing to do is use a site like nutritiondata.com to pull up the info for all your options. There is a Compare Foods function under the Tools menu. You have to have an account, but it's free. You could also just look at them in tabs or put it into Excel or something. I think a mix of several kinds of tubers/roots would give you the best micronutrient content.