How to scale individual particles non-uniformly

I’m trying to find a way to stretch particles over their lifetime. I’d like to be able to animate the scale of the x or y axis of a particle to accomplish this. In Shuriken, you can animate the size of a particle, but that uniformly scales it…not stretchy.

So I haven’t found a way to do this other than the stretched billboard rendering option. That doesn’t work for the animated stretching I’m trying to accomplish, though.

Anybody have any ideas or know of another capable particle system solution?

I also have this problem. Would sure love a sizeX and sizeY on particles.