I have also become recently interested in the staff, but alas, practice partners in 'anything' around my area are hard to come by (rather impossible really).
A good book to get is, "Fighting with the Quarter Staff", David Lindholm. (good beginner's resource though pictures are sometimes poor quality).
For a staff, martial arts supply stores only sell them at 6' max but you can get straight, non-tappered ones. For a longer one I recommend "Custom Bo Staffs" from which you can order one up to 9 feet long (for a pole weapon I suppose) at your desired diameter and material.
http://www.bostaff.com/index.html
I don't recommend Ash if your going to do much sparring with it as the surface tends to flake. Oak, Hikory, or English Thorn are best (though thorn may be hard to get. Lindholm's book also explains how to make your own staff but there's a trade off with the time involved.
Cheers!
Ken