At the risk of sounding a bit harsh... thats what 3rd party escrow companies are for.
You can still employ an escrow company for escrow only,,,no title work.
http://www.timeshareclosingservices.com offers a-la-carte services. or you could hire an attorney
Where you are now, someone has to take a risk...either the buyer sends the money hoping that the seller doesn't keep it and the property, or the seller sends the deed, and risks not getting paid..A deposit would help but the buyer could end up buying for just the cost of that deposit