The speed check on multiplayer is really annoying me, and as a server admin there is no way to turn it off. Many mods such as Tinker's Construct or Grappling Hooks let the player move extremely quickly, but in multiplayer, vanilla Minecraft thinks this is cheating and forces the player to stop mid air. But if the gamerule disableElytraMovementCheck is set to true, the game will not interfere with a player using Elytra.
Knowing this, it must be possible to make the game think that every player is using Elytra at all times, but not actually apply the affects of Elytra (unless of course they are actually wearing Elytra).
I have no modding experience but I am just about to try and get started to make this happen. I cannot say enough how annoying this movement check is. I am very much considering commissioning someone to make this sort of mod happen. If any modders out there think they can do it, please, get in touch with me.