Actually, porting Android to the Touchpad should be way easier than many people think..
Since WebOS is based on Linux kernel, you're solving a huge problem of drivers. The drivers are kernel modules and are available right there on the TouchPad and I belive that HP released (or will release) the kernel source code (they need to, it's GPL).
So the drivers are issue is basically solved, now the next parts
Well, you don't have to look for the source code for the kernel and other Linux packages, it's right here
LOL: The kernel is Built for Android! take a look at their Linux kernel patches