After a few days of searching S could not find a bitter orange. Instead of bitter oranges we ended up with sweet lemons. Meyer lemons are not not quite as tart as regular lemons and they have a sort of orangish finish.
So into they pot they go along with some regular oranges, sugar, a vanilla bean and the five to one ratio of wine and vodka. We'll see what happens in forty days.
This is S's batch; I hope she shares.