Last, the fourth inversion. I have very little to offer here. From the trio to James Scott's Grace and Beauty Rag is this (circled), but the Bb in the right hand resolves internally and the Bb in the bass is easily heard as a passing tone within the Ab7 harmony.
I decided to look at René Lenormand's Study of Modern Harmony (Eng. trans 1915; French original 1912), which is distinguished by its very large number of musical examples. Even he had trouble locating fourth inversions. This one from a ballet by Florent Schmitt (Study, 31) reminds us of the difficulties that can attend the definition of complex chords (Lenormand himself says of ninth chords that "In all the [examples] that follow, the disposition of the parts is very important" [27]). I've written the boxed chords again at the right; to my ear, the second of them is more convincing as a D9. It's the fourth E3-A3 at the bottom of the first chord that gets in the way (and the C4 even makes an A minor triad), where the "cluster" of ninth and third (E3-F#3) in the second chord, combined with the pairing of seventh and root above it (C4-D4), definitely sounds like a chord built on a D root.
