I used to have a fairly lightweight wool circle cloak (lined with silk noil), and it was heavy and generally inconvenient--I used it more as a blanket than a cloak, and now I'm planning to turn it into a dress that I'll actually wear. I've found coats with sleeves, cassocks, etc. far more practical (you can use your arms without letting cold air in!).

That said, if you've tried cloaks extensively and like them, I wouldn't go heavier than coat-weight. Fabrics.com often has pretty nice coat-weight wool and wool-blends, although their stock is extremely variable.