A patch by Oleg Drokin that adds board file, serial console, gpio keys, MMC/SDCard and USB (peripheral) support has been accepted upstream. So Nook Color support is now available in the linux-omap-2.6 git tree and will be eventually pushed to linux-2.6.
Oleg's patches are the bare minimum and kernel drivers for most devices still need to be pushed upstream. These drivers are both in 2.6.32 Nook Color Android stock kernel provided with the B & N source code and Oleg's Android 2.6.35 kernel. If someone is interested in forward port a driver to linux-next, please put your name next to the driver you will be working on. Then others can focus in different drivers to avoid duplicated effort.
I guess that support for this hardware is already in kernel, look at drivers/power/max17042_battery.c and drivers/power/max8903_charger.c
Nathan Royer from Invense is also working in a driver for upstream submission. But as a part of a bigger driver for a Motion Unit Processing (MPU3050). When contacted Nathan said that he is also interested in a standalone KXTF9 driver working in the absence of the MPU3050. So Nathan's patch should be the one to base the porting work.
Kevin McNeely from Cypress Semiconductor is also working in a driver for upstream submission. Cypress driver is not I2C specific as the one found in the Barnes & Nobles Android kernel. The driver is generic, it has a core driver and bus specific modules. Right now implements two modules for I2C and SPI. The driver only supports multi-touch Protocol A. The community is working to implement Protocol B to Cypress driver, a requirement for upstream submission. The work can be found in this github repo
William Marone is working in a Linux port of the wifi driver for upstream submission, its git tree can be found here