Ten Little Indians

How about adding a deadline element to the games?
What if you could make a game whereby after x number of rounds the weakest ( player with the least armies ) automaticaly defaults and his remaining armies turn into neutrals.
I think this would ad an interresting extra tactical element and it would limit the game in number of rounds played.
If you start with 9 players and after every 10 rounds the weakest players defaults then the game lasts a maximum of 80 rounds.
It would also serve as a nice outlet for people's more vindictive behaviour but unlike other games here you would know what you could expect if you agree to play this type of game.
Again I don't know how much work this would be to programme.

How do you define "weakest" player? Also, I would call this game type "elimination" but that's just me.

The biggest problem I see with this game type is that the turn order suddenly because way too important. So I don't see this game type working, as there are too many factors you can't take into account as a player, so winning is mostly based on luck.

The weakest would be the player with the least armies and the playing order would be no more important but that would be compenstated for because players are aware that the player who takes his or her turn before you can directly eliminate you ( in every game you play you have to take this into account anyway, if the player before you is about to turn in his or her cards in an increasing game than that is equally important en turn order is just as important in capital games, I really see no diffenrence, how many capital games are won by players who take their turn before a newbie who left his capital undeffended? ).

But in "Caps" this will not work

I think this is meant as an alternative to Deathmatch, Capitals and Domination.

Imagine you are the weakest, but only by a little bit.
Than you have to attack the but one (or but two) weakest, and hope for good dice, otherwise you are dead.

A gametype like this could potentially put suiciding as a rule to play to win...

That's axactly the point Matty, all the things we hate in normal games would become strategic choices in this type of game.
In capitals this would not work and in fog it would also be a problem.
But in the normal ( everybody can see everything ) this could work.
And yes the turn order would be very important but that's part of the fun, the player before and after you become much more important.
They are important now too, if you could analyse all the games played I'm willing to bet you would find a high degree of correlation in certain types of games ( capitals, domination & high card capped games ) where beginning 1st or very last is detrimental to your chances of winning.
This is logical because if you start with a great starting position but are the last player to take your turn there is a higher posibility that someone destroys your great starting position.
If you start last you have the least tactical options because everyone has allready put their extra 3 armies on the map and when it comes to turning in cards being the last to turn in is often deadly.

In classic risk there are a few cards where you have to elliminate a certain player.
This would introduce this kind of gameplay but in an indirect way.
If you are 1 of the weaker players it would be wise to make sure the player who takes his turn before you does not get in the position whereby it would be benificial to weaken you so that you are the next to default.
You could also inprisson certain players by making sure the player next to them defaults or you could reduce your defended borders by making sure the player next to you defaults.
You would have to calculate at all time the possibilty that you don't attack a player enough and he manages to survive by trading in cards et etc.