If you have a CCD scanner you can scan 3D objects. I have a
CanoScan 4400F which can happily take a jewel case.
300 dpi is a piece of cake for the latest scanners, really. Most of them already go up to 4800 dpi or more, and they're just mid-range. Mine cost me $100 or so.
(A little correction to the article I linked to -- it's not true that you have to save the image every time and open it in another application. You can install the scanner drivers
without any of the bundled software, then from Photoshop CS3 choose File -> Import, and select the scanner from the list. The scanned image will go straight into PS).