Yes I'd really like that. Kinda like an hybrid thing, between a laptop and a desktop, maybe with some advantages of both. Very cool.
The A1200 case is actuallly very good looking. Just change colour to that marine transparent blue like Macs and it's very attractive.
Another advantage is that the itx boards that are coming even have a PCI slot if I rember correctly and a CPU one!! So you could towerise the thing later if you wanted, or just upgrade to a better CPU, and GFX card.
And it's not that expensive.
I'd buy it right away, and use it to play DVDs in my living room. Actually with that PCI slot you could put in one of those Satellite / Digital TV cards and turn the thing into an amazing set top box. Or just run Linux and have little webserver for your site with very low power consumption. .....