Just a couple of quick (and rather minor) notes:

1. Be careful with your terminology; there is no such thing as "Extended ASCII" -- that, or it's so overloaded a term that it's useless. Extended ASCII could mean any character set which is equivlent to ASCII over 0..126, which is to say almost any character set in common use. I think what you meant to say was ISO-8859-1/15 (which are equiv. except for the euro symbol, which is case-invariant).
2. You could also "use locale", after which lc/uc will do the right thing, or you could convert your data to unicode using input disciplines or Encode.