That's what I was thinking really, there are lots of very good double din units around now, with or without an android I terface that would just require you to use the same facia, but would mean cutting the vent trunking a little bit.
It does look nice but I wouldn't really want my tablet in the car, even with a custom rom. A tablet with sim would make it a little better as you could just set it to go straight to a radio app from boot without needing to pair with your phone but again you'll get that in a simpler manner through just a digital head unit.
Tbh when you see double dins that have quite thick fascia panels over them it does look a bit odd too. The photo on that site hides it but if you look from a bit further out there's something not quite right about the looks.
Yup I'm a big fan of Pioneer head units and their double din ones look fine with the fascia in place too. I'll weigh up the options in time. Everything in one unit without the need to route an EQ and hub etc to the glovebox is better convenience but you do lose that cool/unique factor of hard work paying off.