This might sound like a strange way to level up, but I hit the same bottleneck you did, and I ended up exploring the entire world. Ran into some nasty areas that rocked my balls, but after you clear an area (like east shroud, for example) you get a pretty massive chunk of xp for full discovery as well as incremental xp for each new location within that area. I went from 43 - 44 doing nothing but jumping through the map menu and running through those areas completely.

Failing that, make sure you've done all the guildleves (nice xp as well) and dragonrend fates seems to be the flavor of the month.