Hmm, this doesnt quite fit the bill but I had my wedding at the Lodge at Sonoma (in the Stone Barn, which is a private area away from the rest of the hotel) in July 2010. The Stone barn is a structure and a walled in garden. We had our reception in the barn but I know other people have set up the reception tables outside in the garden. Can't say enough good things about the venue and the staff - both leading up to the wedding and during - Brooke, the coordinator we had was so great to work with - planning it from afar she answered all of my nitty gritty questions promptly and in full and really worked with me, taking photos and sending them to me of specific areas of the venue so i could see if they would work for photo displays etc. We had our wedding on a Sunday night (also had a lot of people flying in - which meant that they had to take a day off work anyway, so the Sunday wasnt a problem) which greatly reduced the site fee and the head count minimum. Being a hotel and restaurant, they cater and provide the alcohol themselves BUT we were able to switch out their standard beer selection for a local brewery at no extra cost. Also, guests got a discount on the rooms (which are spectacular) and they all enjoyed the grounds and especially the pool significantly (but then again it was July)- Also, being so close to Sonoma Square (1 mile) was an advantage for out of town guests - the hotel had a shuttle and so people could get out and about for meals etc. Hope this is at all helpful even if the Lodge at Sonoma is not in your consideration list. I hate when people respond without answering the specific question! lol
I got married at Cornerstone in Sonoma and it was a great venue with everything you are looking for. They even have a guest house set back on the property - not sure if it will sleep 10 but probably close to that number!
try looking at the garden pavilion in sonoma, on arnold drive
Click on each tool to see a sample.