There are many ways to achieve what you want from a cue. Making a shaft out of an exotic material, or in a very elaborate costly fashion will not always guarantee that the results will be good.
In the end I think you'll find that hornbeam and maple (or maybe ash) will perform better than most other materials in a pool cue application. You could always core such a shaft with carbon (for stiffness), or balsa (for ld qualities). The traditional materials are plenty stiff for a pool cue shaft.
Lots of people think that the stiffer and denser a wood is, the better it's playing qualities. I don't always agree. By that logic, purpleheart should be a better playing wood than maple, but it just isn't, not by a long shot. Heavy, dense woods give a different feedback and aren't as springy. Shaft should have a certain minimum of "springiness" to them (IMO). This is important for delicate little spin shots etc..
I hope you get the intended result from your shaft creation, but I also hope you realize that the traditional materials are used for good reasons. You can get plenty of performance by tweaking tapers, ferrule materials and joint pins. I recently found out that I could get a lot better feel from my ld shaft by changing ferrules to a different material. I also realized that I want a conical taper and a certain tip diameter on my cues, so I'm having a shaft made to my specs. I feel confident in getting a good performance out of this combo.
Good luck to you.
