I decided to try some Igus Drylin RJ4JP-01-08 bearings on my Delta, but when I extracted the carriage assembly from the rods and removed the original bearings, I found that the Igus were just a little small and there was more wiggle in the bearing holders than I wanted. Also, in the process of extracting the carriage, I ended up breaking the tab on it that activates the optical endstop. These are a tiny bit tighter, so you can get a good pressure fitting on the Igus bearings. Rather than use the threaded on the original mount, this just uses a 16mm M3 bolt, one of the M3 nuts and both washers from the stock mount. I included two versions; the B version can be printed without supports, but I don't know how (if at all) it will affect the output.
The belt clip propers opening is a bit smaller than the stock, so you'll have to gently spread the clip to slide the belt in, but once you've got it in it's definitely not going anywhere.
Hope some of you find this useful. Let me know if you decided to try them out in the comments section.
I'm also working on a mount for a E3D style hotend that uses the stock effector plate that will have a separate cooling fan that can be turned off for printing ABS or PETG or other thermally sensitive filament, so keep an eye out for that in the next few days.
From what I'm hearing, it looks like Monoprice made some adjustments to the original sliders on the Delta, which could account for many issues. I uploaded the Fusion360 archive to help folks make modifications as needed.