It is not possible to implement anything like this in NWN.
Anything that goes on your hands, if given an attack or damage bonus will only apply to unarmed strikes.
But, yeah, this wouldn't even be desirable if we could do it because of the way DR is handled in NWN. If it only gave you a cumulative attack bonus not considered for DR, it would be... considerable. However, as I stated previously this isnt possible in NWN. I'm pretty sure you couldn't even script an item to work like this, barring just putting weapon focus and specialization on the gloves, which I'm not sure are options.
I've seen items like this in PnP (2 ED) but thats a totally different mechanic. And even a LOT of the NWN mechanics is different than 3 ED PnP.
-TV