I come from Belgium and there are a lot of long track over 10km...
Belgium
Bastogne - 1902-1906 : 86,1 km
http://www.the-fastlane.co.uk/racingcircuits/Belgium/Bastogne.gif
Chimay - 1929-1959 : 10,870km
Chimay - 1660-1984 : 10.450km
(Chimay - 1660-1984 : 9.700km
Chimay - 1996- : 4.520km)
http://www.gdecarli.it/Circuiti/BEL/BEL Chimay 1926.gif
Floreffe - 1925-1956 : 13.600km
http://maps.google.it/maps?f=q&hl=&...reffe%201936.kmz&layer=&ie=UTF8&om=1&z=16&t=k
Oostende - 1911 : 32km
http://www.the-fastlane.co.uk/racingcircuits/Belgium/Oostende 1911.gif
Spa-Francorchamps - 1921-1929 : 14,982km
http://www.the-fastlane.co.uk/racingcircuits/Belgium/Spa-Francorchamps 1921.gif
Spa-Francorchamps - 1930-1933 : 14.863km
http://www.the-fastlane.co.uk/racingcircuits/Belgium/Spa-Francorchamps 1930.gif
Spa-Francorchamps - 1934-1938 : 14,950km
http://www.the-fastlane.co.uk/racingcircuits/Belgium/Spa-Francorchamps 1934.gif
Spa-Francorchamps - 1939 - 14,500km
http://www.the-fastlane.co.uk/racingcircuits/Belgium/Spa-Francorchamps 1939.gif
Spa-Francorchamps - 1947-1956 : 14,120km
Spa-Francorchamps - 1957-1978 : 14,100km (Small modification in Raidillon)
For F1 championship, a chicane was added in Malmedy corner for security I think.
http://www.the-fastlane.co.uk/racingcircuits/Belgium/Spa-Francorchamps 1957.gif
There are 2 or 3 tracks near Spa-Francorchamps before 1921 too

, I have a map of them in a book, but I can't take it now.
It is a list, but I think only Spa-Francorchamps, Chimay and Floreffe are interresting.
And personnally, only one is interresting for VLM JT project. It is last Spa-Francorchamps which ISI have already done.