There are a few Jaegers in the 40" range - one benchrest rifle is pictured in RCA, and another in Robert Held's Age of Firearms. There are a bunch of wheellocks with meter-plus barrels in the Graz armory, though I don't know if they are rifled or not. I'm pretty sure that there is at least one with a 38 or 39" barrel in Wolf's Steinschlosse Jaegerbuschen - it has a kind of forward facing hook where the front sling-swivel would be, allowing it to be braced against a wall or branch and leaned into.
Pity about the twist rate. What is the breech diameter?
Pity about the twist rate. What is the breech diameter?