Here is something I have seen, and am certain of: I am the deeply contented, if lazy, owner of the excellent video advertised by this clip:
I sent away for Sarah-Jane Summers' Highland Strathspeys for Fiddle a few months back, and if I haven't memorised every nuance of every phrase of each of the five strathspeys presented on it, I have only myself to blame. It is a most beautifully presented instructional video, very easy to follow, and with nice features like having the demo played in a separate "chapter" (the clip above is one of these) for easy reference, as well as having it played, unseen, whenever you bring up the sub-menu for the given tune. And in case this, plus the movement-by-movement breakdown which makes up the bulk of each lesson isn't enough to drive a tune home, the DVD also comes with a little booklet of printed music.
Here is something else, which I have never seen and which I am still, nonetheless, certain of (yes, I know I'm ending sentences with prepositions; I'm rather enjoying it): I really, really want a set of these strings. One of my friends (who has not yet tried them, but also really, really wants them) brought up the subject yesterday, and it would appear to be highly contagious. Here's a great little article on the same subject (octave strings, not contagious fiddle fads) from Darol Anger, who has actually tried the like.