Hello. I'm interested to purchase so,e as well, if you can send the seed overseas in Italy.
I don't know what "old school" all blue/purple potatoes are, in comparison with the variety that I know here.
But I can tell you what we are trying to do here :
There is a this very old PARLI potatoes, that grow very very well in high mountain but nothing compared to the yeld you got from commercial potatoes at lower altitude and a very antocianine rich potato called Negresse, that s red and white, but become violet when cooked that grow at lower altitude.
In theory they flower at the same time, so we were hopying that some crossing will happen.
In reality this year, the flowering time was separated thanks to increased temperature so we ended up with nothing for sure, and with very few seed as well. But we will know next year...