Is there a hand blender with a metal coupling connection? I used to have a hand blender of the stick type http://www.jmldirect.com/Power-Blitzer-With-Cook-Book-PP5125/

It was pretty good except the coupling teeth were made of plastic and looked prone to fast wear especially if someone hit the power button by mistake before engaging the coupling. After about 6 months the inevitable happened and I came home and the coupling had become a molten lump of plastic.

Does anyone know if there is a brand of blender of this type that has a metal coupling connection. It seems to be the most obvious thing that manufacturers are creating a built in expiry in these tools.
Coupling design matters more than material.  If you make your coupling short and thin, concentrating all the force in a small area, it will strip even it's metal.  Conversely, a well-designed coupling is longer, so the strain is spread over a large area. 

I have a Cuisinart CSB-76 hand (immersion) blender, and it has handled ice numerous times without any problems.  It has a plastic coupling, but it is a good 3 cm long to spread out the force over more material.  If I recall correctly, the professional-grade Vitamix blender also uses a plastic coupling, but with careful engineering to prevent problems.

It is now common to advertise kitchen appliances based on their motor's power (700 watts in this case), but many of these appliances will have mechanical failures if called on to deliver that much power.  I suspect that you'd be better served to look for a lower-power blender from a reputable brand with good consumer reviews.  I don't think the professional-grade immersion blenders I've used in restaurant kitchens are rated to more than 400 watts.

Personally, I recommend the Cuisinart CSB-76, and have never had a case where I needed more than its 200W.