Time to revive this thread!
I am going to start this project myself. I've been doing some testing and I'm sure it can be done looking pretty stock.
I'll break this down into two categories, hardware and software.
HARDWARE:
I'm going to use a Toshiba Thrive 7" tablet. The reason is size. It measures 189mm in width which is just a hair less that the Galaxy tab DanoH used. I'll still have to cut holes into the vents for cables but I don't have a problem with that.
For the vent/grille I think I'm going to purchase the bezel from the Spec.b. It is already designed for the navigation screen so it should be a better fit than cutting up a cubby one. First question: What should I do about the buttons below the screen? (see pic) Or should I use a cubby one and cut the hole bigger?
I'll figure out a way to hard mount it once I've got everything in front of me. I'm sure I can makeshift some sort of bracket that will keep it solid. I'll post pictures of whatever I come up with.
SOFTWARE:
I purchased a Samsung Galaxy player (5.0" screen) that I used for a couple weeks to workout the software issues.To solve the lack of access to the power button I use an app called Setting Profiles.
https://play.google.com/store/apps/details?id=com.probeez.profiles&feature=search_result#?t=W251bGwsMSwxLDEsImNvbS5wcm9iZWV6LnByb2ZpbGVzIl0.
In this app I set up two profiles, One for power and one for without. When the car turns on it powers the device and sets the screen to never sleep. When the car turns off it sets the screen timeout to 15 sec. Plenty of time to shut down anything I have running. I've got other settings/apps applied also but you get the idea.
All other software (Torque, maps, etc) is pretty self explanatory. I'd still like to find a nicer Car Home app but the ones that are out there will do for now.
Now, second question. Where can I get the navigation center grill for a decent price? The only one I have found is here: http://parts.subarupartswarehouse.com/parts/2008/SUBARU/LEGACY/GT%20SPEC.B/?siteid=214327&vehicleid=1440456&diagram=7524455&diagramCallOut=3 but it's over $100 with shipping. I'd be perfectly happy with a nice used one but can't seem to find any. All the ones I see on ebay are cubbies.
I'm going to take my time on this and do it nice. I wasn't happy with the look of the Samsung player in there. It was just too small and I couldn't get it to look right.
Let me know if you have any suggestions. I'll probably start ordering stuff this weekend. The Toshiba thrive is an sale at Newegg.com for $230 through Saturday.