I tried this on WiiSX 3.0, it actually runs full speed when you get into the game - the loading screens and some other static screens drop the framerate to 5fps but FMVs and gameplay is full speed so I would recommend making a savestate once the game is finally loaded up
Einhander will crash and codedump if left on the attract mode
Elemental Gearbolt doesn't load after the first two screens, unfortunate!
EDIT: All of the games previously listed as not working (Roll Away, NHL 2-on-2, Elemental Gearbolt etc,) do work and play on the last released build of WiiSX RX, so it's definitely worth keeping older builds of WiiSX as a backup even if the speed is not nearly as good
https://github.com/niuus/wiisxrx/releases
EDIT 2: Using the older build of WiiSXR, I was able to get games like Soukyuu Gurentai, Roll Away and Elemental Gearbolt to run at full speed, using a combination of WiiSX 3.0, WiiSX RX and WiiSXR I haven't encountered a game that was unable to run yet. The closest game I have found that I don't consider playable is Fighter Maker 3D which runs awful in any iteration of WiiSX