Once you add a decent spindle (and if you want to do aluminum, maybe a speed controller for it as well), you will still be under your $1500 budget with this: FireBall V90 CNC Router - This would be a perfect fit for wood, acrylic, and PCB work. If you take very shallow DOC, it would be fine for aluminum "out of the box" using a Bosch Colt trim router too.
Alternatively, get in touch with John Hansford (he actually crated the V90 design) and get one of his newer designs... microcarve MV3
CAD, CAM, Scanning, Modelling, Machining and more. http://www.mcpii.com/3dservices.html