The reason you cannot find seeds of this excellent small tomato is that the plant has a trademark on it from an Israeli nursery called Hishtsil.  It took 12 years to breed this grape tomato by crossing it with a wild tomato from Peru. They control the production by allowing the public to buy plants but never seeds. (If you see seeds for sale, they are being sold illegally.) The good news is that nurseries should have these plants for sale this spring. The other good news is that you are allowed to grow the plant and then save the seeds yourself for home use. Just don't sell them. The small size and sweet flavour have given the Tomaccio tomato the common name of raisin tomato.  Let us know what nursery you find plants at this spring as I agree this is a great tomato. Keep growing, Marianne Binetti