Sula

I removed mine the other day, to clean them and restore the threads on the bolts that hold them in place.

I was a bit disappointed: they are heavy, and do essentially nothing (beyond looking decorative).

Does anyone make a simple & lightweight alternative? Is that sort of thing at all fashionable?

Prelude Guy

You'll have to go a custom route.

I don't think there's any market for lighter weight tail pipes. The extra weight is negligible in the grand scheme of things, especially since most owners care more about looks than weight.