So, I scrapped Viking D&D for another idea.
I started off by building a much more expansive world, with a continent roughly halfway in size between Australia and Europe. I plan on having around fifteen or so kingdoms, each containing several principalities, duchies, baronies, and the like, and these kingdoms are split between five distinct ethnic groups. My goal of creating a more realistic image of feudalism is in no way influenced by Crusader Kings.
The basic idea of this game is that the players start off with an adventure that places them as level 15 or so heroes, in a setting with a technology level roughly equivalent to the late 1500s; the idea of this particular adventure is that it's one of those stereotypical heroic dungeon crawls and hits every cliché in the book up until the ending.
The revelations made in this one-shot adventure are a setup for the plot of the real game, set about 250 years afterward, where the players play as the distant descendants of their original characters in a sorta-steampunk setting, where the actions undertaken by the characters in the first adventure are shown to have far-reaching consequences because of villainous scheming and such.
Oh, and it would be Pathfinder, because the character classes in vanilla Pathfinder are more in line with the setting I have in mind than they usually do (e.g. Gunslinger is OK because guns make sense in mid-1700s setting; Alchemist is OK because of the beginnings of organized chemistry, and Investigator by extension and also for proto-Holmes stuff; Vigilante... just seems more OK in a 1700s setting than a Shakespeareish one, etc.)
Thoughts? It's still something of a fledgling idea, in that I've just finished worldbuilding about one of the planned fifteen kingdoms or so, but I want to make sure this isn't a bad idea right off the bat.