Colorful sweet corn is not really very colorful at the eating stage - most of the color doesn't develop until its past prime. Still it's fun corn to grow. Nearly 20 years ago, I found an ear of decorative "Indian Corn" in a farmer's market bin, that had a small percentage of shriveled (sugary/sweet) kernels. I grew a row of this dark red kerneled, purple husked type and detassled it letting 'Golden Bantam' and 'Incredible' sweet corns pollinate it. I only saved the shriveled kernels and those have been the foundation of our line up until now.
Last season, I detassled 'Japonica Striped' and 'Piamonte Orange Flint' and pollinated them by our colorful sweets. We grew the F1 this year and detassled again, backcrossing colorful sweet pollen on them. These are the ears we got. When they dry down 50% of the kernels should be shriveled/sweets.
The first two pictures are the Japonica derived ears the third is the Piamonte derived. You can see some of the shriveled kernels starting to show on the ears in the close-up (second picture).