Can't remember if I have bookmarked this one before...

Regency Spenser Jacket & Pelisse Pattern instructions Based off a commercial pattern created (based on Janet Arnold and extant garments) and retailed by the author, but gives a good idea of how to do it. I do like that as a long jacket style, and with military frogging and braid*, that would be rather drool worthy. Doesn't go with the later Victorian stuff but...
*Can we say dark green wool with black cording...

M134940 with Na abundance of -6.5 may have finished running by now.