I was asked this question today and had no idea. The question came from a non-profit that has a working DVR and no budget to upgrade, but wants to improve video on one or two cameras. The analog cameras sound like they're covering pretty narrow FOVs, so replacing everything to increase resolution isn't going to happen.
The WDR cameras I had experience with years ago in the analog days were pretty poor by today's standards. Off the top of my head I'm not sure who even makes a strictly SD analog WDR camera. Any suggestions?
The one thought that came to mind was using a more modern HD analog model and using the SD analog output on that. Does anyone have any experience with that?