ooo.

Yeah just a read of this in the help browser, will definitely have a go with this thank you!

-post Pd tryout edit- THANK YOU!

I am also searching for this.

The standard GEM [triangle] is a bit of a mess.

the only way I can think of making a E-Triangle would be to create 3 [rectangle] objects. Make them X by 0.01 (for line thickness) in size.
Then using [rotateXYZ] & [translationXYZ] position them into an E-T.
Once you have them fixed you could then find out the ratios between the points and then apply motion and other effects to these 3 objects accordingly.

A downside to this is that this shape won't be able to be filled with colour or texture...