I don't know if this helps you, but try telling them that they can leave the 'distributed' part for later. At my company we still have a 'central' repository. We'd really need to know more about your companies objections to DVCS to give advice.

I personally just started using mercurial local-only alongside svn, and as new projects started I would try to make mercurial the default repo for that project. This worked well for me, but my company is pretty laid-back about these kinds of things.