I've implemented a version of this myself but it would be nice have a built in Insert Flash Video option, as well as the insert flash option.

 

Flash video requires a swf player for online use, but there are loads of them out there.

 

The implementation is almost the same as the insert flash option but with a pointer to a flash player before the flv file, and a couple of parameters are different.

 

My version replaces the existing Insert Flash swf option but ideally I would like to have both the swf and flv option.