I picked up a Columbus nGPS receiver on eBay a few days ago. So far as I can tell it's very similar to the official Nikon version, and seems to work well. The only problem I've noticed is presumably a problem with the Nikon version too - I'm using it on a D7000 where it plugs into a socket on the left side of the camera, which is covered by a little rubber door (there's an alternative cable for cameras that have the round multi-pin socket on the front). The plug that goes into the camera is about 1.5cm long, and the cable itself is fairly thick and inflexible. This means that when the GPS is fitted I have the socket cover and the cable sticking out quite a bit. It feels a bit odd and obstructive at the moment, but I suppose I'll get used to it once I've used it more. I'm just a little worried that it'll catch on things or break the socket on the camera if I catch it on something.
What I was wondering is if anyone makes a more flexible version of this cable - ideally one that sticks out a lot less and is a bit more flexible so that there's less chance of damaging things. The socket on the GPS is a standard USB Mini-B type, not entirely sure what the socket on the camera is - I think it's non-standard.
I've attached some small photos to make the situation a little clearer.