I haven't tried it but it seems impossible.

Depends on your perspective of pretty. By human standards, no, I would say impossible. But who knows what another Argonian considers attractive?

I think you'd have to ask Crassius Curio.

Also, since we have no idea on what you mean by "pretty" considering that Argonians are Lizards, we cannot offer any advice. Can you specify your request?

Confirmed by me as well.

I once attempted to make an attractive female of every race. I'd have to say I succeeded... except with Argonians

There's pictures of female Argonians I've seen that don't look bad, and still look like an Argonian, but you somehow just can't escape from making one on Character creation from looking completely insane.

Depends.

I made one that I though was beautiful; I'm not attracted to Argonians, but aesthetics =/= sixual attraction.

/\ This.

not without mods but I've seen pics of a somewhat sixy Argonian that was made to resemble Angelina Jolie from Beowulf

Argonians come in a wide and amazing variety of shapes, colours and sizes. Of ugly.

It's like a scaly rainbow. Of ugly.