I took repeated long exposures, during a night time thunder storm & discarded the multitude of dark frames. I think I managed 3 actual strikes on this occasion.
On another occasion I work up to a storm and kept 2 cameras going alternatively just leaning out of the bedroom window. Much darker then so I could do 60s exposures & it was only during the strikes that anything showed up. That solved the issue with camera shake :)
Here's the brightest one from that storm, all lit by a single strike.
ultra flashgun by Mike Kanssen, on Flickr
I wish I could arrange a flash like that a bit more often, the guide number of that flash must be huge!