One of my main sources was Rodovid, too

I can't find anything on the doc about the Tarakanova branch, so I must have omitted it for the same reason you do (can't remember what it actually was, though) but then, I don't have an Ivan Ivanovich Troyekurov, either, though I have the rest of his family, right down to Leo Tolstoy.
The other branch that I'm pretty sure would lead down to the eighteenth century is the descendants of Anna, daughter of the eponymous Roman Yurievich, in the Sitsky and Suleshov families, but they're just too obscure.
The other interesting line is from Filaret's great-grandfather, who was an ancestor of some Golitsyn Prince who died in 1773 and his sister, who married a Bagration scion. They were the last of their stemma, unfortunately. They might gain from a Paul-is-dead scenario, though, being high-ranking and all.