I know that one of the main reasons people go for MIUI is the awesome customization options like the themes. And i was searching around for themes that were compatible with v4 and couldn't find anything due to upstream bugs. But, I found something even better. Well I think so anyway. I found this thread:
Project Vexillum might not be a full blown theme but I honestly think that it looks better than 98% of other MIUI themes. All this is really is an icon expansion pack for the stock MIUI v4 but for those of you who are anxiously anticipating the port of your favorite MIUI Gingerbread theme, I think this will hold you off until it happens or it might even become your new favorite. At the moment there are about 770 icons but there are new icons coming every day. And if your favorite app/game doesn't have a custom icon if you post a request on the thread with the name of the app and the market (play store now) link there are a lot of people on that thread that make beautiful icons and they get them done really fast. When you go to apply the theme make sure to uncheck the statusbar setting because the 3G moves on top of the bars.
Here are a couple of screenshots of my phone right now:
Hope everyone enjoys this theme as much as I am. And be sure to thank PhysX and all the others that contributed icons that you use.