This is a great idea, though I don't see why it would need to be Sys 3 or 4 - surely Sys 1 would be enough (bearing in mind that it would need to be left with the lid open - charging a battery in a closed box would generate far too much heat).

Having said that, all my drills are Makita, so I'd need one that charged their batteries!

There are a couple of different radios - mines the TL12 (IIRC), which is actually a torch with a radio built into the handle, not the big radio box.

My understanding is that DeWalt owns the patent on the "battery powered radio that's also a battery charger". I know that Bosch's radio also charges batteries, but my understanding is that they pay something like a $20 royalty to DeWalt for every radio they sell. Apparently that patent will be expiring in the next year or two, so be prepared for a raft of updated radio/charger units at that time.

I REALLY don't mind that my Makita LXT radio doesn't charge my batteries. My thinking is this: I want a cordless, battery-operated radio that I can haul all around a customer's home without being tethered to an outlet, or having to decide whether to charge a battery or carry my tunes with me. Besides, I can use my LXT impact driver daily and still only charge my batteries maybe once or twice a week. And when I do charge them, I stick the charger way off in a corner somewhere so it's not in danger of one of my coworkers damaging it.

I suppose one option would be to stick my radio in a Sys 4 or 5, drill holes in the sides for the music to come out?... But yeah, you don't need a huge radio, the BMR100W sounds GREAT and is approx half the size of my old Milwaukee radio. A Sys 1 or Sys 2 -sized Festool radio would be plenty, particularly for inside, shop use