I just went to the Cingular store yesterday and got myself a 7100 series holster:
BlackBerry 7100g Soft Sided Holster, Black
It works like a charm. A little tight (especially with the egrips on), but that's ok with me, I don't want my crackberry falling out.
The magnet works fine too. The baby locks up once I stick it in.
Aesthetics are acceptable. It really looks as if the case was made for the 8700 device.