A posh vacation would be really nice, but if you only have 10 days left to spare and you both have jobs, that might be a little tough to work out... a raincheck, maybe? lol.
What kind of lady is she?
I really can't see how you could go wrong with jewelry. Every woman loves jewelry, even it all it does is "just shine on her wrist or finger or neck." But if you go that route, it must be a piece that reflects her style. Is she an elegant pearl necklace kind of lady, or a bright bold costume ring? A beautiful pair of diamond studs is a classic.
oh, maybe you could get her a day at a really nice spa so she could pamper herself? everyone loves getting pampered but most moms rarely get a chance. although, a a gift certificate for a spa is more like a birthday present. or maybe you guys could even take a romantic weekend trip to one of those hotels up in the mountains or lakeside somewhere that offer great spa packages.