great goal! I have no kids, but can just imagine how hard it is to find time for crafty time, let alone get ahead of those birthdays, etc. But I am a strong believer in the idea that taking some "me" time on a regular basis ends up allowing you to be a better wife, mom, daughter, etc. We need to recharge our batteries.
since your time is limited, perhaps when you come up with one card, you could make a 2nd one that is similar, but still unique -- sort of like CASEing yourself. this could help you to create that stash a bit.