If you are talking about Quake, fans have made plenty of high resolution textures, there is a 2.5GB HRTP at moddb: http://www.moddb.com/mods/quake-epsilon-build

Compare that to the original game data being around 30MB.

Interestingly, fan texture projects almost always have super high fidelity that normal games don't. Most of the Epsilon textures are in the 4kx4k neighborhood.