Thanks everyone for your responses. I've heard a range of possible solutions to address the issue, each with their own merits. I agree with merlyn that using full OO for this small module might be overkill. Some of the other solutions don't allow for two levels of defaults, one of the features I like about my current implementation.

So what I've done is to document the code a bit as it is and release that publically. I'm still interested in further feedback on how to best make this work-- I'm hoping that by publishing the code and documentation the issue will become more clear.

http://summersault.com/software/cascade/cgi_err/

Any feedback is appreciated. Thanks!

-mark