If we try to take that request semi-seriously, then I say it'll be impossible to cast. As it is, casting pregnant girls is tough since they're more apprehensive than before preg even if they were already doing adult. Add multiple partners or anal and they hang up the phone.

For whatever reason in Europe you'd have a better chance casting this (i.e. Germany), but whoever does it first more power to them (as far as the preg Bukkake part, not the other felonious parts that no producer would touch)