I've put a server up with no additional hacking necessary.
It seems there's a rubber zone in sty+ct ( hi hoop

) that will drain your rubber reserves whilst you're inside it or replenish it depending upon the value used.
I first tried CYCLE_RUBBER_TIME 0 but this just stops you from using any rubber thus making you invincible.
So tried hacking the server to allow negitive values to be used with this setting. That worked for the server, but not the client which had no idea his rubber was nearly full nor his tail short so was able to drive straight through his own tail and some other cycles tails if they were high on rubber too. Interesting but useless.
I settled on CYCLE_RUBBER_TIME 10000000 so as your rubber meter goes up it naturally will not go down.
To increase everyones rubber over time there's a massive rubber zone that fills the hole arena slowly adding to everyones rubber. As their rubber increases their tails get shorter. When their rubber is full, they have no tail and they die.
In order to stop this happening, opposite value rubber zones are spawned every 8 seconds. Occupy one of these zones to decrease your rubber meter and lengthen your tail. Each new zone is spawned 50 metres up/down and 50 metres across from the last.
Last Man Standing ftw!
It doesn't really feel like snake to me

It feels hacky but it's smooth enough to be playable. It's fun for a while, and I'm sure there's more potential there.
Any comments, ideas, etc welcome.
Oh, the server is called "Snakes - Eat Food or Die!"