The one from NWTA:
http://www.nwta.com/
deep in the resource area:
NWTA Clothier/Patternmaster
Non-commercial Patterns and Instructions
291 Sporran, circa 1750-80
Free for download, $1 if copied and shipped


(The image is a negative of the one original downloaded)
Get the original from the NWTA

By leaving off the tassles, it can be easily simplified. Also, marine-grade vinal (or a cast off purse at thrift store) can also be used instead of leather.