Do a google.com search for Thunbergia mysorensis - that's what you're looking for.

I talked with Matthew at B and T World Seeds - he says these do exist, but he has no idea how or where one could find seeds or plants.

I just bought a T. mysorensis from Zone 9 Tropicals but it appears that they are now out of stock. You can contact Bob and ask when he's going to have more. There's usually a number of nurseries that carry it. Kartuz, Gardino's and Logees all carry it but I don't know if they have it in stock now or not. I honestly wouldn't buy from Logees because I think they are terribly overpriced for the size plants they send. I've never seen seeds available.

Karyn, I thought she meant T. mysorensis, too, but she emailed me that "no", she is talking about a yellow-blooming T. grandiflora and a RED-blooming T. grandiflora. That's why I emailed Matthew - to ask if they really exist - he replied that they indeed do!

I immediately thought of you when I read his response - I thought 'if anyone knows a source for these two vines, it would be you'!!!!! I just hadn't gotten around to emailing you.

I received a direct email from Karyn who said that the colors I am looking for do not exist in grandiflora. Karyn, they do exist. I just emailed Dow seeds who has them on a list dated 2000/2001 but not on a current list. I have seen them listed elsewhere as well but never a current availabilty.
Cherry

I've never heard of T. grandiflora in any colors besides blue, white and a bluish lavender but there's several T. alatas that come in colors ranging from red, orange, pink, yellow and white. I'm not saying that there's no red or yellow gradifloras but I've never heard of them and I've been growing different varieties of thunbergias for about 10 years.