Recently I've had to fudge Maypole, Class::DBI and friends around quite extensively to get my job done.

Some of the stuff I did to Class::DBI include objects which bless themselves at retrieve/create time based on an implicit class field, objects which pretend they've been deleted using a lifespan table, which contains (has_many) the times in which the row existed. The classes override delete, search, retrieve and so forth, and allow you to create "view handles" into the past, to query the database as it was at ... The list goes on.

All of that has been very easy to do because Class::DBI is very heavily abstracted, both by design and by implementation. Sure learning curve is a bit higher, and you have to juggle more thoughts at once till you're intimate with a bit of code, but the amount of time you spend changing the abstracting core is traded off to time spent extending it, which is a much easier task, IMHO.

Good post, ++!