ARB makes a good one, but stay away from TAG, ot tactical armour group, I have seen more issues come out of that shop than quality peices. You have to question a company that keeps changing there name to avoid bad press.
Other than the poorly-recommended TAG bumper, there aren't any winch bumpers for the 96-00 R50. The ARB sahara bar for the 01-04 R50 (almost $1400) can be adapted to fit. Most other winch bumpers you see on R50s are either built by their owners or are custom one-off builds from a 4x4 fabrication shop. You might get some good advice from folks over at nissanpathfinders.net
Looks like it's time to dust off the welder and torch and try to make one myself. I'd love to have the ARB or a TMJ, even a TAG but looks as though the options are extinct for the R50. I'd like to see where the mounting points and any bracing/other attachment locations should be but I guess I will figure that out as the design/build comes to be. Any input would be appreciated. Diagrams or pictures even more. Thanks to all who replied.
Sorry to be the bearer of bad news, but TJM discontinued bumpers for the R50 around 2000, so really the only way to get one in the US is off a salvage Pathy or stumble across one on craigslist or another Pathfinder forum.