I've seen those extra running lights - they'd be a great addition and could be easily made to flash along with the standard light, or to act normally. You'd probably want them NOT to flash, else having the brake lights flashing AND the turn signals flashing behind the one lens could get confusing.
Unfortunately having running/brake lights inside the turn signal housings is illegal in Australia, as the law specifically states that indicator housings must house only the indicator lights, so I won't be adding them to my bike. (That's why you never seen brake lights doubling as turn signals in Australia, the way American cars do. All Aussie cars have seperate turn signals, like British ones.)
Hmm there's another idea, I'll add an "output" in case people want to connect extra flashing brake lights, as well as a "flash disable" switch. Any other suggestions/additions you folks would like to see?