A quick scan of the interwebs turned up a few banners, but nothing had the Oldhammer Beastman vibe I was seeking. So, I pulled up a generic banner drawing and, using Gimp, blanked-out the artwork. Then, I searched through the WHFB 3rd edition books for something suitable.
At the bottom of page 73 of the Armies book, I hit the jackpot:
After scanning the image, I used Gimp to erase the shield on the right. I also cranked up the contrast and then "posterized" the image to make it a more clear black-line drawing. A simple cut-and-past job resulted in the following:
I used generic white printer paper, as I was in a rush. So, I painted the back of the paper in a watered down tan craft acrylic. Then, did the same on the front, and added some very watered down maroon and mustard yellow acrylic paints - basically creating something akin to watercolors.
I cleaned up a few of the black lines with a Micron pen (where the paint was too heavy, it obscured the lines), then cut out the banner with an Exacto knife, painted the edges with a darker tan (especially on the bottom, to make the banner look more dingy), and then sprayed the banner with Testor's Dullcoat. A dollop of glue later, and voila:
I've since rolled the edges of the paper a bit to give the banner more of a three dimensional look. In any event, not bad for about an hour's (not including a ten minute delay, when, like a complete boob, I dropped the banner and I had to crawl around on my hands and knees looking for it) rush job, I think. The hand-drawn look captures the Oldhammer aesthetic just as I'd hoped, without requiring any artistic skill on my part.
I'm looking forward to doing something similar for an old metal terminator squad. Next time, though, I'll plan ahead and use better materials and spend more time in Gimp cleaning up the image.