The hackingtosh concept has been going around ever since I can remember with home computing (earliest memory was ~1987 on modified Atari STs that used the 68000 processor just like Macs did at the time). IIRC you couldn't actually buy one or be supplied one by a third party (otherwise their lawyers would come down like a ton of bricks) but you could buy the constituent parts and do your own at home (afterall it's unlikely they'll know and regardless of licensing terms it's unlikely they'll chase you for your own machine). If I remember correctly on the Ataris you had to solder a particular ROM chip yourself onto a daughterboard (again, nobody would do it for you), other than that it was relatively straight forward.
I personally don't understand the fascination with Macs. They're nothing special, arguably underpowered for the money and I can't see the benefit personally over a PC. Obviously if there's exclusive software & hardware then it's a no brainer (eg. video editing package or sound recording console) but for software thats available on both systems it doesn't make sense to change over to me (no matter how many people keep telling me, they've never offered a convincing reason).
Take your point, just mentioned it as many people have done this before without any major problems...
Indeed they have, but Apple will have fun one day as they'll be logging their IP addresses for future use as the machines show up as having non-standard configurations and with the new laws they'll be able to tie the IP address to a particular physical address at a point in time.
You can buy hackintoshes on eBay made to order.