Google Earth (maps) currently already has 3D versions of all American Disney parks. They're not "street view" worthy (the graphics quality breaks down at the ground level, but check out the screen shots I attached), but it's actually pretty accurate and fun to fly around the properties. In fact, most of the country has this 3D feature, where it's not just a flat image, but actual 3D texture mapped buildings, landscape, and landmarks. The Google Maps website lets you see this if you click on the "tilt view" icon, but It works
much better if you have the actual Google Earth software rather than just going to the Google Maps website, as the PC software allows you to pan, tilt, rotate at will with the mouse. You can even go into a rudimentary flight simulator mode (controllable by keyboard, mouse, or even gamepad), and fly anywhere you want. The flight sim mode has some drawbacks (sometimes the detail is still loading while you're moving around), but the regular free-view mode is amazing. You'll often feel like you're actually flying over the Earth rather than looking at a graphical reproduction, and if you have a 3D monitor and 3D capable software (like nvidia 3D or tri-def) you can actually view it all in 3D.
As for street view, several other tourist attractions (the ones already mentioned, along with some of the Six Flags parks) already have it available, so it wouldn't surprise me to see it for WDW.
