Yes it could be done.
Well kinda, I mean you could replinish their health as its lost while they use the shield.
I wouldn't make it a weapon though, just a entity with a hotkey ( :scancodekeypressed=x:state=y ) in the script to activate it.
It could have a semi-transparent HUD to give the player a chance to see it in front of them, while still holding and/or firing their weapon.
You have to have conditions checking the character's health when they activate the shield.
Then depending on the players amount of health they are set to various states.
Each state would monitor the players health and add any that was lost during the use of the shield.
That would be a timer started when the shield was activated.
SO..
if the players health > 350 then goto state 11
if the players health > 300 then goto state 13
if the players health > 250 then goto state 15
if the players health > 200 then goto state 17
and so on
If the players health was 349 then state 13 would check for the health to drop below 300 and if it did then it would add health.
When the timer is up then take them back the the original state and the health will be taken off as usual.
Of course if you had 349 health the shield would leave you at 300, so you lost some health but never over 50 if used in a structure as in the example above.
I haven't tried this, and the engine might not handle those conditions as intended.
In that case you would check for health >50 then goto let's say state 11
Then state 11 could check to see if the health was > 100 and move on, if < then it would so its thing.
The next state would do the same thing and see if it was >150 or if < then do its thing for the 100 to 150 range.
Does any of this make sense?
( would 5 seconds be long enough ? )
Post Script
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