Yeah… Theme Manager is working on MIUI Android ROM finally. I am testing the latest MIUI 03-12-10 and using Hastarin 8.5.1 oldcam Kernel from xda-developer, lesjaw ~ Jaws-MIUI. Everything is looking good to me especially the theme. Too bad that it does not have Miren Browser built-in (but you can always install it yourself). HTC Sense lover can install MIUI FancyWidget Mod to make it more Sense like.
For detail installation, please visit xda-developers. For me, I copied the ROM into Android folder instead of Jaws-MIUI-RC1 so that Android launcher is working. Applied patch 1 only and changed the startup.txt to avoid failed to boot into Android HTC HD2 issue.
Installation guide ~ How to install Android 2.2 Froyo on HTC HD2?