do any of these have the option to not charge the ipod
Sure. Take your ipod off the dock when you're not using it....
The JBL speaker does not (at least I haven't found it if it does). As a self professed battery freak, I use the 3.5mm plug for the ipod at least once a month until the battery dies. The other three weeks I use the dock, but take the iPod off the dock when I'm not using it.
Sometimes, I will also use the AAA battery option instead of plugging it in. This will also not charge the iPod.