No I havent, But have you looked for the different ways they mount? you know that web search thing..
Ortlieb Trunk Bag < Product Details | The Randonnee Shop
You Got the Ortlieb bag? a second rack top mount part can be Bought.
Measure the width of your intended rack and compare with some of the PDFs that Ortlieb posts from their German Site.
Yeah, I don't have a seat post rack yet, so I have some flexibility. The Kwikfix mount works really well so I think this rack may be just the ticket. Otherwise, you are correct about the different mounts.