Since you require sqlite anyway for the POI data, why don't you just store the track data in a table as well? There'd be additional benefits, like being able to compress old tracks to once-per-minute checkpoints (or just the track breakpoints) in a simple operation, faster startup (Maemo Mapper takes a long time to start on my 770 if it needs to load a big track in), easily limiting the track display to just the last hour/day etc..

I'd be happy to help design a good DB representation for maps, routes, tracks and POIs, which would take efficient indexing into account, if you want. Send me a private message or email if you're interested.