The more I consider OO in Perl, the more I'm inclined to agree with tye's insistence that inheritance should be avoided (at least in Perl)
Well - I wouldn't go quite that far :-) Although inheritance is often overused in designs - regardless of the implementation language.
As annoying as these issues can be I find I don't get bitten by them very often. The problem is that it can be a complete bugger to track and fix when it does happen.
There is also the problem that the lack of these abilities, even if they don't impact many real world situations, can be used in those pointless "perl cannot be used for coding in the large" flame fests :-)