Is there a way to make regular software in Windows 8 appear as a Modern UI app? I know I can simply run desktop apps fullscreen, but that doesn't provide the convenience of swiping from the left to switch apps; I can only swipe onto the desktop, from which I have to use the old-style taskbar to switch desktop apps. Alternatively, is there a way to make Metro apps appear as a regular app on the taskbar? (This I very much doubt.) Whatever it is, I just want a little more consistency.
Yes. I'm not sure how you could do it though. If the title bar of a Desktop App is removed (including the min./max./close buttons) and it runs in full screen, it would appear to be a Modern UI App. One such example is Google Chrome. If you set it as the default browser and launch it from the Start Screen, it would run as a Modern UI App. I doubt Google officially supports it, instead, I think its Windows that wraps it as a Modern UI App.