Yo! Before youse guys put pencil to paper, there are points to consider. My experience with designing unit patches , taught me this:
1). Less is more.
You are not creating an illustration that is going to be hung on a wall like a framed painting. If as stated, it is to be recognizable from a distance,........think of military patches......Simple.
2). Quantity.
You are going to be required to have a minimum order. Is this going to be a worthwhile endeavor? Will you have the required number?
3). Colours.
The more colour you have, the higher the reproduction cost.
4). Size.
This is related to "Point #1". Keep the detail down or you are going to create a blotch....not a patch. Will it fit on a cap? More people wear caps; less wear shooting jackets.
n.b.: If I were doing this, I'd choose to use black thread on a white or light-bright base fabric while working with simple design in outline only.
Gofuhvit!