Dear Friends,
the proposal: http://wiki.openstreetmap.org/wiki/Proposed_features/Street_area
is already over 15.000 times used in the map. See: http://taginfo.openstreetmap.org/search?q=area%3Ahighway
The russian OSM Community has already special map which shows streets as areas in highest zoom level:
http://openstreetmap.ru/#map=18/55.77224/37.49369&layer=K
With regards,
Marek