Dean,
If it is hard there it is worse here. A few years ago I went up river from the Brazilian border to Iquitos, Peru. At a stop on the river I bought some regional tomatoes as they called them. They were quite good. I brought the seeds back and they did ok. But, I lost them unfortunately. Here in Amazonas they call them cats paw tomatoes as they look like a cats paw. I wish I could find some more of them. Chrerry tomatoes do well here. But, they do not make great sandwiches. Over on the mouth of the Amazon the Japanese graft tomatoes on a relative the Jurubeba and from what I hear get good results. But, it is bit of work to do the process.
dk