Purging old versions

Hi

I was wondering if other people would find it useful to purge old versions of a 
page.

I have a few pages in my wiki which change on a regular basis and as such my 
revision number keeps climbing and thus the amount of different copies of that 
page.

My thought was that as well as having the delete function would could have

a) ability to delete a revision ?

b) to delete all but the last x revisions ?



Alex