[Goober5000]

http://www.hard-light.net/forums/index.php/topic,45352.0.html

[Snail]

Couldn't that be done manually using the shields-off SEXP?

But that doesn't make it any less cool.

[jr2]

Couldn't that be done manually using the shields-off SEXP?
...

Nope.

Do the shields get weaker as the subsystem gets more damaged?

Try it and see.

does it have support for more than one shield system?

Yup.  You can have more than one shield generator just like you can have more than one engine system (or weapon system, à la Inferno's Sol Gate, or sensors, or comms, etc...).  The game code takes care of that internally.

Also, as Taristin said, do they work like the weapons and sensor subsystems on your ship?

Yup.  If the overall generator strength is above 50%, shields are at 100%.  If it's below 50%, shields decrease logarithmically to 0.  Also, if the generators are below 30%, the shield isn't 100% reliable.

EDIT: just remembered - what about shield storms? 

Huh?

Those things aren't shield generators...

Yeah, officially, they're sensor globes.  Bor-ing.  Unofficially, everybody knows what they are.