Chosen Solution

For example, can the camera from the 3GS be installed in an older 3G? Are there any parts that are interchangeable either “off the shelf” or with slight modification between these phones?

I doubt it. Unless you study an iPhone like the people who write jailbreaking softwares do, you won’t be able to do it.

Well for the parts that have extra features (I mean, for the parts you’d actually want to install) you’d probably need to, aside from all the hardware work, change whatever parameter makes the iPhone OS believe it is either the 3G or the 3GS. Not discussing of the feasibility of such a thing, it would then require you to change all the parts that are different from one model to the other so not to cause software issues. (e.g. the phone relying on some hardware feature that actually isn’t present.)

hey could you not just change the logic board and the dock connector? would this not work?

the part that comes with the headphone jack,volume,vibration and sound buttom, and on/off buttom… from 3g work perfectly with 3gs i just tried it and woks perfect……