Going back to warcraft 3 days, particularly when I played frozen throne, there was a map series called footman frenzy. You can read a detailed account below

http://frenzy.wikia.com/wiki/Footmen_Frenzy
http://strategywiki.org/wiki/Warcraft_III:_The_Frozen_Throne/Footmen_Frenzy

In brief it was a custom game with a maximum four teams of maximum of three players. Typically each player had a base which produced one unit every few seconds for which upgrades could be purchased, the objective was to wipe out the other teams bases. On top of this their were Tier/Base upgrades which gave access to better units, 'creeps' which were ability based additional units and heros. Hero's would be much like your spiral knights character for sake of argument for those who never played WC3. There were other versions, 6v6 Footmen, No Heros, Pro (which forced you to take a hero instead of changing tier at the start of the game), and Onslaught which was 6v6 with elements from Onslaught from UT2k4. That last one never took off, probably as the 6v6 and Orcs vs Humans variants were already around.

Thing is that this game type would make an excellent Spinoff or possible new multiplayer mode for SK, which is pretty much a Zelda MMO as far as I am concerned. The basics of the game are effectively already there, look at the bomb and lockdown arenas and you have the control objectives. Change those to some of the BattlePods, have them produce units and set the objective to be defeating the other teams and you are basically there.

There are two routes you can realistically go down from there - four teams or two teams. The two teams system would basically be players bases producing units, which can be upgraded and unlocked and charging at the other side for a big balanced fight in the middle. Add an extra control to the game which lets your Knight call in the closest units to follow or following units to leave and return to the main fight. I play on a joypad so it's just mapping another button, anyone else it's a keyboard key or mouse button. Want to try and out flank a bunch of enemies? fine, but you could just use it to hold back your injured units from carrying on, let the next wave charge through and then lead a small force to help over power the enemy and push through lines. Or you could just charge in and hammer your opponents leveling up weapons and such. Four team is done in a square.

If you have WC3 and haven't played FW then go here http://www.epicwar.com/maps/search/?n=footmen+frenzy&go=1 for some of the maps that were available. Not sure if anyone still plays online though.