I have the same problem. My Neo Retros won't fit the narrow unicrown fork my bike came with. They go on, but they really ball things up if a tire change is necessary, because the cool stop pads don't fold out of the way. They aren't adjustable in the pad position in such a way that the angle of the arms can be tuned for proper function.
One option if you have the NRs already might be a Nashbar fork, it's wide, and I have heard good things about it. Unfortunately my ride uses a 1" tube.
The other option I am contemplating until I get things fixed up (I'm planing on making a fork) is these brakes by Nashbar. They are inexpensive, and have adjustable regular blocks. I've always had the regular blocks and they seem to work fine if one can get things properly set:
Maybe Tektro or someone has a better execution of this concept...
I found several things about the neos, that seemed to require custom installation. I don't like the way they fit on regular canti bosses, I don't like the way they require to be designed for a particular fork width, canti spacing and rim width. But when I build my fork I expect to be able to dial all that in and the results should be more what I had in mind when I first bought them. I haven't tried mounting them on my MTB, but it would probably be fine. They weren't designed for my touring bike so I'm not criticizing the brakes, it's just one of those peculiar compatibility issues.