Is there any work going on related to 3byte support for Polylines and Polygons. In principle this should be the same as for POIs which are already in the 3byte form. With OSM Composer there is now an easy to use GUI for Mkgmap that greatly enhances the need for more definitions. This is due to the possibility to copy any object and assign new tags to it based on criteria (this has been possible using perl but now it became comparably very easy). I.e. you have a Polyline tagged "Highway=track; Bicycle=yes" then you could automatically retag this to something like "Highway=bicycletrac". Or "Highway=track, track_grade=3" to Highway=track3 and render it in a different color. It's too possible to copy objects. Instead of retagging you could now overlay a color code around the track indicating the trackgrade. You would now have two Polylines one Highway=track and an identical one on top of it with "track_grade=3". (I hope I am doing everything correct here, never posted on a mailinglist).