I've found both Mirliton and Corvus Belli to make very nice miniatures to paint up. However, your example miniature is far from "a horrible sculpt" compared to the average 15mm models. Sorry to burst your bubble, but if you really want to show of your painting, 15mm is not a good choice. *...

Haha, that machine is huge! I need one, not I just have to get an army to fit it in.

I am painting the same Mirliton Late Crusaders as Hospitallers, though I am keeping them as a small DBA army while I finish my first Carthaginian FoG army. From what I have found, the Hospitallers started to shift from the black and white design to a red with white cross at some point in the middle ...