If you have this ambition, I would look into an older version of Cyanogenmod running on a piece of equipment such as the HTC Dream or G1 original or the HTC HD2, which is a veritable swiss army knife handset on the XDA Forums, which came with Windows Phone 6.5 (i think) and is capable of running windows phone 7, 8 and Android as well, which is pretty miraculous for such a device.
Originally Posted by patapoof
The G1 was the first android device which came out around the original iPhone 3G....and there were users in the XDA Developer community able to run even 4.0-4.1 android on it - again, an amazing feat.
There is software on the forums which allows you to cross or compile ROMS meant from one phone to a completely different device. I would hunt for one with comparable specs and then seek to use a converter tool I believe it might be called a "kitchen" of some sort, but I honestly have never used it and forget the name off hand) to make the leap to the HP Pre3. I am not a developer, but a heavy rom junkie, and have had about 10 different Android phones since they released.