I gotta say, only a 3D purist, and within that class of folk, the even-smaller class of purist, the 3D framing purist, would have a need for a lay-on valley sleeper.
Then there are those, rarer still, who want it beveled. In 3D. And textured to look exactly like #2 SPF, or SYP, or whatever.
Sadly, no, you won't get this in Chief. But you can dream. Short of that, and way too utilitarian perhaps, for your taste, you can show it in a CAD detail, and call it out on the roof framing plan with a nice dashed CAD line, to show the framing sub what to do. He probably will never look at the drawing. The ones I know wouldn't.