I like the idea of having "parts" in the random ID.

This seems like a really complicated way to do something quite simple. I just put up my own version. Maybe I just don't get what you're trying to do, but...

http://www.bytemycode.com/snippets/snippet/579/

While your script generates purely random passwords (which are stronger), this script prefers weaker passwords that are more easily remembered.

For example:
generate_ID(2,3)

Can only generate 6 character passwords of the form abc123, abcabc, 123abc, and 123123.

generateId(6) (your code)

Could generate any 6 character alphanumeric password

very nice indeed...

I like the organization on the code. Good work

El buen pupilo es aquel que supera al Maestro.