I probably wouldn't.
While your heart may be in the right place, I can say from experience that when someone says "ooh, per request, we made a donation instead for x person" it creates an awkward feel to the entire thing.
(maybe it shouldn't be awkward, but it's hard for that not to be uncomfortable for everyone...the giver [who may be thought to be shirking in his gift-giving duties] and the receiver [who will be busy trying to assure folks that no, of course this is what she really wanted, but of course she doesn't begrudge them their material exchange] and the rest of those watching the gift openings [who are wondering if the giver was rude, the receiver really didn't want to play, and if they should try something else next year])
Perhaps camera acessories (memory cards, lenses, flash, tripod)?