Hi
I seem to be in the same spot as I was back when I started collecting information on the GNW and Scanian war. I even have a set of Ersatz Swedes from Minifigs USA (not my favorite figures too much flash too much prep time).
I cannot find any 15mm flags. Oh I have beautiful illustrations from Mr. Holgund's books and from printed PDFs from the web. I even once tried to paint some of them myself. No skill, not even on stylized stuff for 15mm.
Look at some of the pictures on the Essex site for their European Armies 1650-1745 period 15s. Those figures are painted at about my skill level, and thus, it has always been.
Then there are a handfull of 15mm flags in Mr. Danes' Lace Wars scenario book for the GNW.
On another site they suggested that Mr. Schorr sold these 15mm flags on his web site or that Baccus did. There is no more website and Baccus if they ever did don't appear to do it now.
Is there a source? I can't get a web search to reveal any.
Roger55 Beware the Stork
