Maps I tried:

•  http://www.kleineisel.de/ralf/gps/garmin/ (linked from  http://wiki.openstreetmap.org/wiki/Hiking_Map)
•  http://wiki.openstreetmap.org/wiki/User:Computerteddy (Germany + typ + relief!?)
•  http://wiki.openstreetmap.org/wiki/Topographic_maps_for_garmin_devices

Things to try out on OSM:

•  http://wiki.openstreetmap.org/wiki/HikingBikingMaps (not about Garmin)