I agree, one of the most beautiful species of duiker. It seems as though the LA zoo has baby red-flanked duikers born every month, maybe Europe could ask for some.
Really beautiful, yes ... but this species IUCN category is LR/cd, and EAZA offer other duiker species (Ader's duiker, Abbott's duiker, Jentink's duiker) in the "Recommended taxa not maintained" in European collections category ...
I know there are a few european zoos which are very interested in red flanked duikers.
The Bioparco Valencia plans to import 6.6 yellow backed duikers to europe in the next years, so the US Zoos are now breeding this species only for europe. And maybe with the first import of this duikers, the red flanked will come to europe.