I too find it irritating when other wireframing tools don't have that one thing I am looking for. The ability to easily create your own on the fly sounds interesting.

Handful of questions:

Drawing with a finger/pen on a tablet... will the lines auto-smooth? Is there a scripting language under new elements? Would I be able to combine elements and make a reusable gallery type super element?!

Will my clients have to install something to view my templates? Can I send them a URL or will I have to export an image?

Am I asking too many questions?