You can do that in Dungeon Fantasy, which is basically just GURPS with a bunch of pre-made classes and stuff. But the strength of regular GURPS is the ability to handle any idea you can throw at it. It really shines when making your genre-bent homebrew come to life. Once you get comfortable with how the system scales things, you can really just wing it with monsters on the fly.
You can do that in Dungeon Fantasy, which is basically just GURPS with a bunch of pre-made classes and stuff. But the strength of regular GURPS is the ability to handle any idea you can throw at it. It really shines when making your genre-bent homebrew come to life. Once you get comfortable with how the system scales things, you can really just wing it with monsters on the fly.