rather than from sources in each nation (although it all comes from Eurocontrol).
Have you ever tried to get an account and talk to the Eurocontrol servers direct? Apparently they've got an XML-based API that allows you to query their NOTAM servers direct and in real-time. That API is of course specifically created for applications such as this.
I just tried to search the EAD website for the reference, but all I got, ironically, was this:
The European AIS Database (EAD): Tomorrow’s AIS Provision Today
[an error occurred while processing this directive]
I remember that Alexandra (from Orbifly Met'Map fame) has done some work on this as well, but I don't really remember if she actually succeeded. They try to depict NOTAMs on a map too, although it looks like they simply ignored the coded position line and tied NOTAMs either to the FIR, or to a specific airport. They also don't limit the NOTAMs to 48 hours in advance.
MET'MAP - ORBIFLY FLIGHT SCHOOL - IFR ET CPL AMERICAIN EN EUROPE - FAA IFR AND CPL IN EUROPE