I absolutely love this blank from Diamondcast, and we make a number of these pens come show season. Here is one in our basic model. Straight lines, tapered, and postable.
This was not the pen I actually ordered. I ordered one without a clip. But Jim Hinze was kind enough to personally deliver one with the clip to the SF Pen show. I really like it. One suggestion: I put a very small amount of silicon lubricant on the cap and barrel threads; both now rotate more smoothly.