Feature Request: raw body in format strings

I've asked here whether there is any way to get the full content of a commit in a format string and got no replies. What I want is close to "%s%b" except that "%s" will be the first paragraph wrapped into a single line.

Looking at the code I see that there is no way to get that, but it's really easy to add it. Does it make sense to do so? I have a change that adds a "%B" that does just that, and it seems that it works fine. (But I don't know what's the procedure for sending patches.)