This is probably the obvious response, but i've been getting a lot out of "Blues You can Use" by John Ganapes.
It starts with the boxes, but goes on from there (and there are two sequel books) - what I like best is the example sheet music (and CD track) for each section, which is always something more than simple scales.
I know what you mean, but some instructional videos are better than others. The ones that are all done in extreme slow motion with lots of talk of "Now put your third finger on the fourth fret of the sixth string" never fail to confuse me.
On the other hand, I've been liking the ones from iVideoSongs - they do the song in short, manageable chunks, and they display the tab before they start showing you.
I try to play it with the tab, then watch the video to get the subtleties (timing, bends, muting, etc) and it works pretty well.
Those ones aren't free, of course. There are lots of free ones on Youtube and a few are good - but I do tend to learn with the tab and then watch the video to further my understanding...
