I've recently invested in a wireless kill switch, it's a Scandinavian-made device called MOB+.
The receiver unit is wired into the kill switch, and you keep a wireless fob on your person. If you fall in, the receiver kills the engine. This gives the protection of a kill cord without needing to be physically attached. You can also manually stop the engine by pressing a button on the fob, which is handy when mooring up.
Wiring in is fairly easy, four connections are required: Ground, +12V, and two for the kill switch. It does mean you have to get access to your existing kill switch. If you have a side-mount controller you will have to open it up, but if you have a console controller like most 26Ms, you just need to open the console side panel.
You then need to cut a hole (about 2") to fit the receiver. It needs to be visible and accessible - the front is a push-button, and it displays indicator lights. The console is the obvious place on X & M boats, on other boats it will depend how your engine controls are configured, but somewhere near the controller is probably best.
I recommend taking the +12V from the ignition switch, so the unit is only powered up when the engine is on. Wiring to the kill switch can either be in series or parallel, depending on a) whether the switch is close-to-kill (most engines), or open-to-kill, and b) how you want the MOB+ to inter-operate with the physical kill switch.
My switch is close-to-kill, and I've wired in series. This means I don't need the kill cord to be in position at all. The default state of the MOB+ is to kill the engine, so to start you have to press the fob button to activate it. In the event that the MOB+ were to completely fail, then the kill cord can be fitted and the operation is as if the MOB+ isn't there. To get the same effect with an open-to-kill switch you need to wire the MOB+ in parallel.
It's currently available from Force4 and Wetworks, the latter being significantly cheaper.