We have used Luca Garapa of
www.hillsandroads.com twice about two years ago. It was a lovely experience and I highly recommend him (as I have several times before on this and other boards).
He picked us up at our hotel, drove us to various small Tuscany hill towns, wineries, etc. We stopped for coffee in the morning, lunch, and another snack later in the afternoon. He is a very safe and excellent driver, he is very knowledgeable about his country and loves it greatly. He is actually the "reason" we fell so in love with the area that we continually return for visits.
If you know what you want to do and/or see, tell him. If you don't as we did not, write him your likes, dislikes, requests, abilities, etc. and he will tailor-make an itinerary for you. We back and forth e-mailed several times until we came up with an itinerary that we liked. Since we were traveling with my elderly Mom (2 sisters and her) we chose to use a private guide rather than trying to do it alone. It was much easier on her and it made the day much more pleasant and easy-going.
His prices were extremely reasonable for a private tour. He speaks several other languages, along with Italian of course and English.
Very highly recommended. Good luck.