You know, I looked pretty hard for you and I think there's NOT a trivial solution.

You can either get the Flip Ultra (not Ultra HD)
+ Works great with standard TV
+ Underwater housing
- Isn't a high-definition camera

-or you can get...

The Flip MinoHD 60 MIN VERSION (not 120)
+ High Def
+ Composite Output (so says http://www.theflip.com/en-us/Products/specs.aspx)
- No underwater housing available

Or you can get the Ultra HD -- the one I have -- and just not be able to watch it on your TV, which obviously sounds like a deal breaker.

Bummer!
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The charm of fishing is that it is the pursuit of what is elusive but attainable, a perpetual series of occasions for hope. -John Buchan