Castle or medieval tower lodging in Tuscany?

There's a big Malaspina castle in Fosdinovo, Tuscany, that is also a hotel, and not far from Cinque Terre: http://www.booking.com/hotel/it/castello-di-fosdinovo.html?aid=354603&no_rooms=1&group_adults=1 There's a picture and short description in this article: http://www.apathtolunch.com/2016/12/great-italian-hill-towns-near-cinque.html

Here's an article about how to find more: http://www.reidsitaly.com/planning/lodging/castles.html

Since you are doing this for your kids and not adults ; there are some nice old world hotels in San Gimingano that may give the type of feel without actually having to stay in some distant castle.

Staying in town inside San Gimingano walls you can walk to many things and have towers and medieval looking things all around you.
They wouldn't understand but staying otherwise in the middle of no where in which every thing is a decent drive away just cause the castle is cool to stay in would probably mean the kids have less fun overall than being able to get gelato a 2 minute walk away.

EDIT: That link Mike sent does look very cool!

Thanks so much! I ended up finding a cool looking one 18 minutes from Siena, which works well with our schedule. You guys are absolutely right - since it's to thrill the kids, it doesn't have to be utterly authentic. Altho this one looks pretty cool that I booked and has great reviews on TripAdvisor (except for a lady who was mad about being inconvenienced for her Christmas Day arrival)

Here's a gorgeous one in Tuscany, but it's about $1,200 a night. Sleeps about 13 people tho. If I were traveling with a few other couples, it would totally be worth splitting 4-5 ways: https://www.airbnb.com/rooms/13464