Yes, several.
Homebriefing has been around for years. There is EuroFPL, mentioned above, and some others appear to be setting up.
Anybody with an AFTN terminal, even if located in Mongolia, can do this. The trick is making it commercially viable. If one was only filing flight plans, with no supporting service for stuff like delays, cancels, closures, etc, one could do it for next to nothing.
Homebriefing has been pretty good and I used it for about 5 years, but they let me down, apparently due to staffing issues, badly and at the worst possible time. This was an isolated incident, I am certain, but clearly there is no single solution to this; one needs two methods.
I have never seen actual downtime with AFPEx and for the "99%" UK PPL popping over to Le Touquet etc this works fine, and one files both flight plans from back at home.