I reckon the stone pitched trail off the top of High Stile would count. No video of it yet though until my mate Dene edits it.
Doups below Skiddaw would be good. I have lots of pics but no video.
My mate Donald and I riding off Buchaille Etive Mor down the middle col and down the grass into Glen Etive was pretty steep as was the descent I rode last year off Stob Binean. It was like bloody skiing as we linked turns to control our speed. I'll check to see the GoPro footage he has to see if it captures the steepness of it.
The descent down to the saddle from Beinn a Bhuird would look good on film. Again, only pics I'm afraid.
Sooooo, I'm not much bloody use for this thread!