Tom, I stepped back from this question and decided that my answer was a bit of a “half donkey” effort. Part of my answer stems from my using a raised panel router bit to create beveled drawer bottoms. I started doing it that way before I seriously got into hand planes and I guess I never broke the habit.
I’ve always (and I mean every single reference) seen beveled drawer bottoms housed in square grooves even though the edge of a beveled drawer usually is shaped to compliment the groove you have. I never personally liked using a square groove to house the wedge shape of a beveled drawer bottom. So, I liked using a raised panel bit which leaves a square edge inside of a square groove.
Hopefully that explanation is clear as mud.
However, I still was uncertain about what the textbook answer was based on historical precedent. I have a relatively extensive collection of books on late 17th, 18th, and early 19th century North American furniture.
I couldn’t find any specific references to a groove of that shape. Not suggesting it didn’t exist, I just was not successful at finding an example.
So then I looked for an example of a period molding plane that would cut that groove. There is a plane called a “snipe bill” but that’s probably not what we’re looking for. Bottom line, once again I had no luck.
Lastly, I thought there may be a modern shaper or horizontal router bit to cut that shape. I did a quick search and didn’t locate a specific cutter but I believe it’s out there in someone’s catalogue. After all, you’re holding stock with that groove cut in it. That means the bit is in existence but I wasn’t able to quickly locate a specific example.
A “Drawer Lock” router bit would possibly cut a similar groove but it’s typically intended to cut across the grain for assembling the drawer boxes. Perhaps there is or was a larger version that would cut that groove.
I hope this is of some use.