There are lots of scientific papers on the biodiversity of grains and how much variety there is. (e.g.,
http://journals.plos.org/plosone/articl ... ne.0069371)
I looked around a lot but could find no one selling grains that had a stated level of biodiversity. There are plenty of pills that at least claim to have a particular diversity do; I used Hybiotics PRO-15 before I switched to kefir. I had already tested them to see they have at least viable probiotics (putting the ground pill in milk for a day and it formed curds/whey).
Since I could not find grains with even claimed diversity, I just found some local grains and then added a Pro-15 pill (crushed) to a few batches to innoculate the grains with a diverse set of the strains. I've also added various other things, like yogurt with particular cultures. I figure I'can give the grains a boost every few months to help ensure the diversity, but they are growing so fast I have not. You can see my grains on one of my videos
https://youtu.be/WymzVVPokh4My grains that big grow from a split-off .5in grain in about two weeks.
Happy to ship you some for the cost of shipping, but you can probably find like ones locally and culture them with some good pill, which is probably better as shipping requires drying which will change the biological diversity.