Is it possible that a plugin can be made which allows both the placement and setting off of TNT via a permission? I have various groups on my server and I would only like the donators to be able to place/set off TNT. Most I've seen only allow or disallow the placement, and Essentials has it on or off globally. Is this even possible?
WorldGuard? If you have WorldGuard (which I highly, highly recommend for any server), then you can set blacklists for TNT placement, ignition (use), whatever. Hope that helps.