I think the biggest issue your going to face is the fact that Qualcomm has never been keen on giving out architectural sheets on their chipsets. Since most newer chipsets incorporate improvements from older models, it would be akin to them giving their competitors access to some very guarded information.
The odds of them giving the design to you without you representing a company that is licensing their chipset for use in a phone, greatly decreases your chances even further.
On a positive note, bypassing the battery should be relatively simple, however, as with all lithium batteries there is a voltage control mechanism built into the phone that you will need to adapt to function properly with a different type of power supply.
As for the monitor, the odds of you being able to adapt a VGA/HDMI cable to a system that is designed to read input from the touchscreen/digitizer is another chore, and would require you to pioneer something from scratch.
I would say your work is cut out for you.
If you really want to do something like this, buy a Raspberry Pi when they hit. It'll be much more adaptable to what your looking to do.