It’s already possible, though not ideal, to implement races in a server using a combination of More Player Models, and permanent effects mods or plugins.
I had races implemented in a former server (as many other servers do) and plan to keep and improve this feature in a possible future server.
Some thoughts on your proposal:
- this is something that has been ruled out for future LOTR mod evolutions, so it definitely has to be implemented in another mod
- setting skins from the LOTR mod is feasible as More Player Model and Morph manage to do it
- setting the player’s height and eye level is also feasible as earlier versions of the LOTR mod worked with that More Player Model feature
- there is no reason to limit the number of races to those you list. For example, I would love to be a 7 blocks tall Ent and just stomp upon the little creatures crawling on the ground :-)
- customization and cool GUI are nice-to-have rather than must-have features for a dedicated mod
- letting players use their own skins could defeat the purpose of a race mod if they select something inappropriate or intended to deceive other players
Some thoughts of my own about the way I wanted to implement this:
- Player Characteristics mod
- Player’s race mod
- additional features would be required for special cases such as Beornings (shape changers), but this would also be in the nice-to-have category
- it would also be nice to have some restrictions on the tools used by some races. An Ent shouldn’t be able to use most of the mod’s armours and would probably have no use for swords and that kind of things (toothpicks for them!)
- these special cases should probably be implemented as additional mods...