The Wacom tablets you see in the store are usually no bigger than a 5"x8" which really isn't much space to write as the tablet is not proportion to your screen you would have to write small to get a decent size on the screen and the cursor can jump to different locations on the screen without warning. I wish there was someone that was close to you that had one so you could at least give it a try.
But there isn't going to be a simple out of the box solution for what you want to do.
The closest thing I have seen to what you are looking for is one of the digital white boards. you can write on the white board using an electronic pen similar to the wacom tablet pen and when you want to erase the board you push a button and the screen gets cleared. But they are extremely expensive for an individual.
I was looking at the Bamboo tablets and the ones that are a step up. I liked the size of the Adesso, but I did not like the fact that it was a battery operated system and not USB powered.
Okay does anyone here have experience with the Graphire by Wacom? I found one, and seems to be what I need, especially that it has bluetooth, and I can walk around my classroom with the table which is nice. Also, experience with the Adesso CTz12 which is USB powered and has a large active area. I really want to get rid of my overhead and try using this stuff.
This may help.
Id say go with Wacom. I have used plenty of them, and never really heard of any problems. They are the biggest player on the tablet market.
And thats how you get ants!
I love teaching math on a smart board, because i can work out a problem on the board, and then just make a new page for the next problem, and can go back and refer to the previous problem for students who fall behind, or for those times when I show them that the concept is the same between the two problems. It also comes in handy when we are graphing equations. I don't save my notes like you are trying to do, though. I also don't use the handwriting recognition either. I guess I just never needed it.