Blacknmild, did you really say "My coins are likely to expire before I see something I really want."? You DO know that coins don't expire for at least 2 years after you earn them? From the Club Nintendo FAQ:
Unredeemed Coins will expire two (2) full Club Nintendo years (July 1 - June 30), plus whatever is left in the current Club Nintendo year, after they are earned. Example: Coins earned in March 2009 would not expire until June 30, 2011.