I found where REB can be downloaded. The problem is that a purchased license key is needed and I see nowhere to get that. If you really want the module you might try contacting Thought-Sight Consulting Inc. to see if you can still purchase it. Here is the link http://download.thoughtsight.com/
Regarding the NEB, it is one of my favorite versions to read and I have two hard copies of it. It would be fantastic to have it for e-sword. I have also thought about contacting the publishers but never have. Let me know if you need any help with this project. Currently I can find no bible program where the NEB is available. I think in the 90's it used to be a part of Bibleworks but it isn't anymore.