Here's an example of how to interface to the Newhaven 5" capacitive touch touchscreen.
I'm using our DVI Graphics shield along with the touchscreen plugin.
But, this can also work with our NH4 adapter, Newhaven's adapter or your own adapter.
Should work with the 4.3" capacitive screens too with required changes to the display portion of the demo.
The interface is I2C, so it's was really easy to write the driver.
It tracks up to 5 fingertips, so it's kinda cool.
Also, it can detect the zoom in and out gestures all by itself.
5p0_CapTouchTest1 - Archive [Date 2012.07.15 Time 15.36].zip
Update: Now have it working with the low cost NH4 adapter and have a $3 breakout for the capacitive touch connector:
You just have to run 4 jumper wires as shown in the photo above...
Update2: Now demonstrated to work with Newhaven 5" LCDs...