Is there a hand blender with a metal coupling connection?
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.