Thanks for the link to the pics of Black Striped Heart, obviously not the same as the striped plum from Barcelona (I adore this city too) but they certainly look similar!!!
I forgot to add that the "Striped Barcelona plum" has very dark flesh that must be dominant because all 5 seedlings were dark fleshed, but it didn't pass down the tougher skin it has so I guess that's not dominant.
As to the future of tomatoes, who knows???
But it is super exciting. I'm tinkering with striped tomatoes because I got hooked by the superior taste and disease resistance of Large Barred Boar and Berkeley Tie-Dye Heart from Brad Gates in my climate (oregon), and because they create a wow in my network. But I can tell you that on my small farm I won't be tinkering with the anthocynanin gene anymore. I'm too small an operation to get rid of the antho taste effectively while maintaining the color/health benefits. I'll leave that to the bigger operations.
Here's another pic of seedling #4.