Do you want to ride fast or upright? Have you rode bikes before - What kind? Do you have back or flexibility issues?

What is your idea of 10% off road? Is it something like groomed packed dirt trails at a park? I've rode through groomed dirt trails with 32mm tires with almost no tread (Continental Sport Contact tire). The ride was bumpy, but uneventful. I could feel the tire slide a bit every once in a while, but I was also going only about 5 MPH.

Perhaps something like the Marin San Rafael could work. It has an adjustable stem to give you a more upright position, but if you ever end up craving the need for speed, you can lower the bars and go faster.