Here is my suggestion as someone who has modified hundreds of wood and metal lathes for cue work and built a lot more cue lathes than that. Let the cuemakers on here know what your present budget is for a pen lathe. Then we can think on what lathe you could be used to build pens with and also be able to maybe do some cue work on it with a few modifications. A wood lathe with 36" center would allow you to do sanding and wraps on cues with a few additional parts. But if your budget is $850 then you could get a good penmaking lathe that is already set up to do tips and ferrules on cues. Then you could add some things to that to do more in the future. So without knowing your budget we are all spinning our wheels.