Yes I'm still pursuing this actively albeit slowly. As a matter of fact I recently did some 3D work trying to figure out my options.The main options are still 2 and I'm as stuck as ever to choose between them and the many variables.
Thin: uses a thin-itx motherboard and a modified GPU with a displaced heatsink. Means less customizable by the user.
Thick: Uses normal ITX motherboard with low profile cooler and double slot GPU. More options for the end user.
A third variable is still the screen and whether it should be integrated, with the electronics board located in the base area or simply a Vesa mounted screen that users can choose to buy for themselves (and is attached to the lid area of the laptop). A fouth variable is whether to include the PSU in the base (eg FSP500-50FSPT) or use external power bricks
A small treat for those who didn't know about this mobo (including myself up until recently) The Asus ROG G20 motherboards are really interesting. They are low-profile, they are powered by two external power bricks and they have plenty 12V connectors to power a GPU (even a 12V screen?)
It would be ideal if Asus would sell these B2B but I doubt they do. If anyone knows where to inquire please help!
If any people on these forums feel they have the experience to help build this you are welcome to get in touch.
PS, just upgraded from a 560ti to an rx480 and been lost in fallout 4 for about a week now. I hope I can get to work on this rather than play games all the time.
Obviously I didn't go the exact same route you are planning to do - I never intended for a keyboard on my rig. I do think that utilizing a large laptop screen for the monitor will save you considerable heartache (and possibly let you relocate some components up into the lid). It is also very power friendly, as right now with an i6600k processor, 750Ti, 1x SSD and 1x 3.5" HDD + screen being powered off PSU I pull less than 155~W while benchmarking with Heaven. There is definitely room for some improvements - utilizing a DC-DC PSU, custom wiring harness, etc would let me footprint significantly.