Flying Squirrel, I know what you mean. I'm always wishing for more toys, too. If you put the word out, you might find someone willing to saw for you, though small independent sawyers like me aren't always easy to find. As far as being scared of stuff in urban trees, you mean things like this?
I found this 3/8" anchor bolt in a walnut tree. Five minutes for a blade changes and $32 for a new blade and I'm back in business. One slab of that walnut more than paid for the blade! Hope you get the chance to play with a sawmill. I bet you'd love it. There's nothing like opening up a new log and seeing the beauty inside it for the first time!