I wanted similar genetics and just got a pack of Northern Lights #1 and Humboldt Purple from Classic Seeds at The Seed Depot. These are supposed to be real old genetics from the 70's. Got the Afghani #1 from Seedsman.
If you want to find a real gem in the plants, you will either get lucky or grow hundreds to thousands of plants. I mean something above top quality clones already being used. In other words, not practical for a small time grower.
The Afghani was $35 or so and the other 2 were $45 each, so good prices too.