This pattern for a seamless, gansey-esque cowl in two lengths, Everything But The Gussets, is available on Ravelry. You don’t need to be a Ravelry member to buy it.
I’d love to hear from anyone who’s knitted it. If you are a Ravelry user, please link your project page to the pattern page.
The construction is a little challenging, because the edge bands are knitted first, in the round, and are then joined by working the central section back and forth between them. But the pattern has been test-knitted successfully, the instructions are detailed with charts for the stitch patterns, and there’s a diagram to show how it all fits together.