Sounds like a Joe2006 is what you need....cuts wood and plastic easily at 60-80 ipm
You won't need the linear slides.
If you go with a Hobby CNC kit the controller gets real easy.
Software you will need is Mach3, some CAD (lots of free versions) and a CAM package..
Cheap one is SheetCam.. http://sheetcam.com/ but vcarve is what I use most now.. http://www.vectric.com/