Below is a list of current iodoom3 forks that are worth checking out.
A GLSL backend for iodoom3
As it stands at the moment the doom3 source code only supports ARB shaders, this is inconvenient because most shader programmers are used to languages like GLSL or HLSL rather than Assembly. This fork remedies it by extending the functionality of the engine to include GLSL shaders as a possibility. This fork is particularly good for those of you looking to use the Minimum assets pack as that currently requires that you have doom3 for the arb shaders. As of writing this the fork does not yet work with the Minimum Assets Pack, though one would imagine that will change in the near future.
Copy the doom3 assets to the base folder and make sure to change the default config file to reflect this change
This enables the GLSL renderer
64 bit doom3 source code
As it stands at the moment the doom3 source code only supports 32 bit compilation and 32 bit libraries, this fork allows the binaries to be compiled to 64 bit, especially helping 64bit Linux users who would otherwise have a tough time trying to compile as a 33 bit.