Using laptop parts (and a little bit of ingenuity) this could actually exist.
You would need:
A custom shaped shell (with designs)
A custom shaped motherboard
A custom shaped LCD monitor (touch screen if you want).
Custom sound system
Oodles of screws.
A hard drive (this could be a Solid State [SSD] or the traditional magnetic. The SSD will be more expensive and will also have a shorter life, but it will be way faster than the regular HD)
At least 8 GB of Ram (4 is what is ok... but the computer will slow down after many updates.[quicker than with 8])
AMD or Intel processor (Intel would be preferred)
Power supply (mainly a Li battery)
A CD drive (or go the apple rout and make the user use a USB one)
A keyboard (or the more fancy laser keyboard)
A GPU .... Graphics card.
and a Network drive.
(for the OS... you can use Linux.)
All this would cost you roughly... as much ,if not more, as a high end gaming PC.
If you get me the materials I would put it together for you
You might want to take the other guy's advice as well. He seems to have way more knowledge on the specific parts required, and could probably give you a better estimate.
(it is best to go in with as much information as possible.)
If there is anything I can help with, just ask. I would be happy to help if I can!
But that's really cool of you to out line exactly what will be needed ^-^
well... more of a general check list. As computers are pretty persnickety about what will work and what will not. If I stated a specific motherboard, I would also need to state a specific ram and processor. (I really didn't want to do that research as laptops are a little bit harder to make from scratch... much more effort and planning ya know?)
[also I forgot the cooling system. oops]
Wellllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll.... they look pretty cool... ya know... even if they would be considered out of date in 2 years.
(I actually want to take a crack at those fish tank PC's. =])
So... if I am getting this correctly... you agreeeeeee~?
Also with the weird angles the case would have, It would be better to have a motherboard that would complement the case... I wouldn't want to have any loose fitting parts ya know?
I was thinking that the hard drive would best fit into the (for a lack of a better description) pointed bits, where the other would be able to hold USB ports and or Ethernet connection/ wireless adapter. The middle would have plenty of room for the power and the motherboard n' such. The cooling system is the main problem I am having. (planning in my head that is) [you have any ideas?]
I think the Casing would be where the bill would skyrocket.
Actually your desktop idea... It is friggen' brilliant!
If you just hide the actual PC somewhere (that will still be accessible, and have good airflow) you can make the object in question the keyboard and screen! It would also be easier, cheaper, and would look (/run) better!
Though the printer would need to make the casing more solid though. That would call for a little bit (like half a spool) more plastic.
The keyboard could be placed in with a notch allowing for the USB cord to be hidden. (or you could use a wireless) The screen would have to be built in though.
I would think it would be more of a fun second monitor than a main, dew to the... interesting... shape of the screen (you could have it off to the side like in the game)