Hey I am 6'3" as well and ordered an XL in my grandpa's jacket. It's regular length but by no means "a bit longer".. Compared to my Analog jacket (also XL), and more loose fitting, it is a slimmer fit. Regular length for a 6'3" guy in the XL.
Edit(May/10): I have long arms but my cuffs poke out about half an inch past the jacket when you have the cuffs over your hands, if not they do not show.
Also, I think the AK Blaster jacket is what you should look at if you want something a bit longer fit in the XL.