Happy Birthday, Mark!
Get a lathe with a 1 3/8 spindle hole, minimum 10"swing. You don't need much distance between centers when the spindle has a decent thru-hole.
I have a brute of a lathe, 10" swing, with only 20" between centers. The key is the spindle hole, where a barrel can be loaded into the lathe thru the spindle hole, and set 1/2 beyond a 4 jaw chuck. Steady up the free end of the barrel with some long tapered pine wedges, or make yourself a centering collar to steady the barrel with.