Peter,
Due to the continuing ambition of wood suppliers to reduce the dimensions of pen blanks (20mm used to be commonplace but nowadays 17mm seems to be the norm) it is becoming increasingly difficult to produce the larger pen styles. And they've increased their prices to boot! Personally, I don't attempt to turn anything like the Roman Harvest unless I have a decent stick of material large enough to achieve the goal, and that is becoming difficult to achieve. So, you have my sympathy for your problem, and my admiration that you were able to produce that gorgeous pen that you show on your other post. Well done, Peter!
Bob.