Well, you can't have it ... not exactly. But you can have something pretty close.
A Touch Diamond Skin for Any Windows Mobile Pro/Pocket PC
Click here and follow the directions. You'll need to download SPB Mobile Shell and the HTC Touch Diamond Theme Skin CAB file. You won't get all the features of the Touch Diamond but it's not bad.Here's a video demo of the HTC Touch Diamond Application on an HTC Touch:
