As long as we're talking precedents evolving -
A personal favorite is Benny Howard's DGA-6 Mister Mulligan of 1934. It was designed specifically for high-altitude long-range racing, but was good enough to win the unlimited closed-course Thompson race too - (with a little luck when Roscoe Turner blew a engine in 1935).
And it was the only racing design to evolve into a successful line of private aircraft DGA-8 through DGA-15.