As I've said before, an 'all-in-one 1.0x-1.5x-2.0x telconverter' is very unlikely. The patent referenced in the post is a simple adapter patent with 4 elements in two groups. This is not the magic TC we're hoping for. Move along. There was a separate patent for a switchable 1.4x-2.0x TC that was actually for a TC, basically a 1.4x with a second 1.4x in a flip-out design, that one could actually exist.
To the topic at hand, I like Oreos. The 1.4x would be a regular one, the 2x would be Double Stuf. But I agree that black versions would make sense, though I'm not sure how many people frequently use a TC with a 70-200/2.8 (but Canon probably has a good idea).
Worth noting that we can already make Oreos with the RF 100-400, RF 600/11 and RF 800/11.