OK. In 2009 I crossed Dr. Wyche's Yellow (f) with German Red Strawberry (m). I've written about this cross here before, but maybe not with the same pictures I'll post now.
Both those tomatoes are large, indeterminate, regular-leafed, and late-bearing. Dr. W. is an oblate (flat) yellow tomato with lots of juice and pulp and good flavor. G.R.S. is a red heart tomato with little juice and pulp, lots of meat, and excellent flavor. The first photo here shows left to right the parent varieties, German Red Strawberry and Dr. Wyche's Yellow - with the resulting F1 hybrid in 2010 on the far right.
The F1 hybrid in 2010 wasn't terribly interesting. The crossed tomatoes were all identical of course, and they were large, red, late, semi-hearts - "meatier" than Dr. W. and with more pulp and juice than G.R.S. The flavor was good, but nothing special.
The F2 generation in 2011 was unstable (as it's supposed to be) and fascinating. The 12 plants I grew produced several distinctive kinds of tomatoes and several different foliage types. All were regular-leafed, but foliage ranged from sparse and wispy to extremely thick. Ripe tomato colors of red, pink, and orange appeared on different plants, but most plants had tomatoes that looked and tasted a lot like the red semi-heart F1 hybrids. I didn't pursue those strains.
I planted three different strains of this cross last year - those were the F3 generation in 2012. At this point I've discontinued one, put one aside for now, and I'm planting seeds for the F4 generation in 2013 of one strain only. I think it's a new stable OP variety now, or very nearly stable, and some other folks are growing these out this year also. This is a large, orange, late (I think) semi-heart that's very meaty and has excellent flavor. Last year's F3's are shown in the second and third photos.
I think this still-unnamed variety will be a good new OP. The net effect, I believe, has been to add some characteristics from the excellent German Red Strawberry (improved flavor, more "meatiness", semi-heart shape, and darkening the ripe color a bit from yellow to light orange) to the already-fine variety Dr. Wyche's Yellow. The cross displays some improved characteristics from the Dr. W. parent also - thick non-heart like foliage that protects against sunscald, and it's more productive than G.R.S.
The second best source is Carol Depp's book titled How to Breed Your Own Vegetables, now in paperback, 2nd edition.
Timber Press Books are pretty pricey as well.
For many years a friend with a degree in plant breeding used to send Craig LeHoullier and I some of those F1 seeds from crosses he did, but unlike OP varieties, when the seeds are gone, so therefore goes the hybrid. LOL