I've got a very simple mod here for you, but also quite useful.
All this mod does is opens up a few of Minecraft's hard-coded rendering values, and lets you configure them.
Currently, you can change the rendering distance of mobs/players, as well as the distance of the nameplate above the players head. This could be very useful for PvP modpacks!
This is just a quick 1.7 port. I plan to add config file reinforcement from the server which forces values to take effect in the next update. This means that no matter what the client user wants, the server will set that value.
The config is incredibly simple to use. You can toggle nameplate and entity altering with the two booleans, and set the values with the integers and double.
Value-wise, the nameplate ones are the distance in blocks that the nameplate will render from. Anything below 2 will completely disable nameplates. As for the entity range, lower values means a LARGER range. 0.5 will double Minecraft's setting, 0.25 will quadruple it and so on. Lower numbers also mean more resource usage, so try and find that "sweet spot". Default is around 80 blocks.
That's all there is to it! Enjoy, and please comment with any ideas and suggestions of what else you'd like to be able to tweak!