I dont know about the flashing type - do you have a link for them??
Im assuming that the standard LED's have a delay on lighting up due to the series resistor on them. Flashers would have to negate this.
I have access to a whole host of LED's in my line of business - might be worth seeing if i can come up with something
These are the ones I was looking at from RTBB (#89's). I don't have specs for them but if they are brighter and sharper than the existing #89's then I will give them a go (just on topper to start with)
http://www.rtbb.com.au/catalog/index.php?cPath=22_119_121
