There is a variegated salvia greggii that is a hybrid of S. microphylla and S. greggii red...and from experience of growing it, believe that this hybrid also has jamensis in it's heritage. The hybridizer denies the parentage of jamensis, but has confirmed the microphylla.
The Autumn Blaze developer reports that the Autumn Blaze is from a sport of a red-blooming salvia greggii.
I have found that the two plants are often confused in the market today by both purchasers and sellers alike...and a great deal of mismarking or absense of plant tags is common.
I have found the variegated jamensis hybrid to be unstable in the variegation and a much less hardy plant than Autumn Blaze. The S. microphylla x greggii demands shade, more moisture, and basically is a high-maintenance prima donna in the test garden in TX...
Autumn Blaze has proven to exhibit consistent variegation, long-blooming period (9 months to date this year), and all of the hardiness we have come to expect in a greggii. The over-all shape of the plant is mounded and it does not seem to 'cover' itself in blooms as other greggii exhibit, but it presents a consistent bloom over a much longer period and begins before most other greggii.