Know that you mentioned desktop space being a concern w/anything you use, but I finally justified buying a Desktop Apprentice at Staples. Bought mine at a reduced price as someone had returned theirs and the box was all torn up:
Staples® The Desk Apprentice™ Rotating Desk Organizer | Staples®
I increased the storage space it offers even more by using s-hooks to attack rectangular shallow metal mesh 'baskets' from Target onto 2 of the outer compartments. Big tho it may be, it keeps a ton of my oft-used stuff close at hand.