I'm pondering over an idea to offer several different "optional" weapons to Nexuiz that could be enabled in the menu. The weapons would replace normal weapons of the server's choice, or would be selectable by hitting the # twice (hitting it once selects rocket launcher, twice selects new weapon).
The way I'd want to fit this in the menu is to list each optional weapon with a slider bar next to it. The slider starts in the "off" position and, as you slide it from left to right, moves from "laser" to "shotgun" to "machinegun" and so on, indicating the weapon this gun is meant to replace. In addition, there is a checkbox for each weapon that says "<this weapon> is a backup", or something else meaning the weapon doesn't replace the selected weapon but instead sits in the back, waiting to be selected by hitting the number twice.
This way we could have a melee weapon that could replace the shotgun, machinegun, or any other weapon (or go into the same slot as a backup). A lightning gun could be used to replace the electro, cryo, or whatever weapon the server felt like replacing or adding to.
And, like most all options, these weapons could be enabled permanently for a single map in the mapcfg file. So, a certain map might have a Redeemer-like weapon that replaces the rocket launcher or nex.
Another strategy would be to have 9 checkboxes for each weapon, allowing it to replace multiple weapons at once, but I don't see a huge need for that at the moment.
The way I remember the weapon handling code, this wouldn't be too difficult to implement at all.
Some thoughts for weapons:
Melee weapon (like UT shield gun, since a swinging weapon might be hard to pull off without player animations)
Redeemer-like mega weapon
Plasma cannon
Mine gun (for ctf maps)
and so on...
Another thought would be some menu mechanic to allow you to mix up the primary and alt-fires for weapons. For example, this would allow you to give the cryo rifle the electro's alt fire, or make a rocket launcher + railgun (nex) combo, or give the hagar an alt-fire mortar.
Just some more thoughts...