"Poor Little Rich Hero (Meis Rule):" If the hero comes from a rich and powerful family, it will have fallen on hard times and be broke and destitute by the time the game actually starts.
This is really the opposite of the farm boy who has come to the big city to make good; this is the sophisticate who comes to the farm in order to learn the true value of family, friendship, loyalty, et al, so that when they win the crown and head back to their sophisticated world they can take with them the down-home goodness of honest folks.
Really more of a fan-fiction thing than D&D, as I would guess more than half the people who sit down to write a Terry Pratchett-style book begin with a character of pure, noble blood who's estranged from an evil/misunderstanding father and loving mother, who must 'succeed on his own' ... or crap to that degree. I don't find players follow this one up very hard - I can think of a few who make a note about a misunderstanding father (its always the father, isn't it, since our fathers never seem to understand D&D), but it never seems to go anywhere.
Of course, in a long-term sandbox game, there's not much desire on the part of the DM to make everyone an ex-noble of some kind ... because it creates large problems where it comes to group roleplaying. Do you A) make sure that everyone in the party is an equal noble person of the same rank, to end jealousy?; or B) do you encourage other members of the party to play roles that are respectful of the one party member who is of noble blood?; or C) do you downplay the whole noble thing when it comes up?
Well, the three questions above assume that there's some kind of generation system in place to determine the social status of your players. Otherwise, the question becomes, is everyone noble or is everyone not? How many DMs are going to point to player two from the right and say okay, you're Prince blah-blah of the Kingdom Yah? I don't imagine that the DM that did would then follow it up with, "You're rich, you've got a personal bodyguard of forty men, from whom you have absolute loyalty." Seriously, are you going to play a thief standing next to that crowd?
Well, I would have issues.
More likely the DM will pull out the old saw, yes, you're a prince, but you've got no money, the kingdom is being run by your uncle that married your mother, and your father's a ghost, etcetera. What's more, the kingdom of your birth is a long way from here - but yes, you have noble blood.
On some level, it might be fun to be a second rank player in a party like that, struggling to keep the prince alive against all odds, restraining the prince from doing anything foolish, fighting ultimately towards the goal where the prince could be reimposed upon the throne and all could be happiness and spoils.
Except for one thing - the male player who is playing the prince is almost certain to become the biggest prick in the universe. Such is D&D.
Nerds and geeks being what they are - ie., not gentlemen - there is bound to be a dearth of noblesse oblige, something that can be measured by how many special benefits/privileges that you as DM give to the little snot once the dice come up that say, yes, this fighter is of noble blood. Give him anything and he's certain to become the Marquis St. Evremonde by the second session. Give him nothing and he's apt to pout and whine that what's the point of being a noble if you can't lord it over your friends?
Now, I've been decidedly masculine in my adjectives for a reason - simply because I believe you have a much better chance of party solidarity if the girl player of the group happens to be the one of noble blood - even if she's playing a male character. Women, by and large, tend to handle this stuff better, with a sense of the dignity and responsibility that comes from being a noble person, without all the strutting testosterone that inevitably becomes the crowning center of a heavily male D&D contingent. It reminds me that I should write a post about pissing contests in D&D ... but we'll leave that off until later.
At any rate, I do have a system that allows for a very low chance of an individual being a noble; and I've always presumed that this RPG cliche would be carried forward; I've twice had a noble person rolled up. The first was successfully put on the throne of a small, regional country, just before the campaign ended permanently. The other had died, unfortunately, at fourth level before anything could be done with it.
But now I'm thinking how interesting it would be to introduce a new player into a long-time party, who happened to be a noble. Think of it: I start everyone at 1st level, which is a huge trial for new players who find they must play side by side with 7th-9th level characters. I don't have a party that pushes noobs around (my gaming group is 4/7ths female), so it works out that if the noob keeps their head down, does a small bit and lives, they go up to 4th or 5th very quickly.
But how would it be if the 1st level did start with 40 personal armed guards, led by a sixth-level-fighter and several middle level chiefs and sub-chiefs? Not henchmen, mind you, as these would have their own agenda - keep the king's spawn alive while seeing to it that he/she got some experience in the wide world - but they would be something to reckon with where it came to power plays within the group dynamic.
I think I've just talked myself into drawing up some guidelines ... someday.