Ian, this is on our roadmap - but I currently see the priority of this as relatively low, given two things:
1) Few comments on this thread
2) As I understand, the idea is that your members will get a bit of SEO benefit by having a link from your site. It seems to me that this benefit would be imperceptibly small in most cases, given that it's just one link and that your own site is not a very high ranking site in Google.
One other factor is that we need to wait for version 5.0 (~late summer 2012) which will have new CMS and new architecture for displaying all functional pages, only then it would make sense to consider changes to member directory.
I would appreciate feedback.
Dmitry Buterin, Chief Apricot