Mini machine tools can be absolutely terrific for modeling. Startup cost is very expensive (it would be difficult to get a decent mini lathe and mill for under $1000 USD), but their usefulness is limited only by your skill and imagination. Some examples (all in 1/24)-
Scratchbuilt alternator
Intake plenums
Ferrari shifter gate and pedals
Brake rotor and beer can
I highly recommend
Sherline tools and accessories, as they are as close to perfect for modeling as anything made. You can get a small Sherline lathe and a vertical milling column that will give you all the utility of a small mini mill in addition to the lathe without having to buy a separate lathe and mill (this is the setup that I have now). There's alot to learn (and as mentioned it's expensive to get started), but it can give a vast new dimension to your modeling.