Yea, dream on!
How great would our lifes and phones be if such thing was possible.
Obviously it is not or we would not need ROM cooking.
Good luck asking M$ and HTC for their code though.
To be perfectly honest, some code is exposed in Platform Builder (M$ tool for creating WM ROMs) but even if you have the Windows Mobile version of the tool which is only available to OEMs it is still not enough.
You need the BSP (Board Support Package) which is something only the manufacturer of the device has.
Pleas avoid making multiple posts. Just pick a forum and post there, even if it is the wrong one someone will find it and direct you where to go, or a moderator will move your thread where it belongs.