I've got a build coming up that I'm doing with a custom case and I'd like for the psu to be completely out of sight. Sort of like a laptop power brick. Dose anyone know any very long psu extension cables that wont set my house on fire?
If you are talking about the cables leading from the PSU to the Mobo, You would be well advised to make your own if you need runs that long, I am only addressing your question though. Why is it so important to not have the PSU in the unit? anyway, if you do this, unless you have mad cable management skills, you will have a nice colorful 6' braid of wire running from outside the case to inside and unless you braid them, it will look far worse than the PSU being well managed internally. you COULD run a bunch of 8 inch extensions back to back I suppose. It just sounds like you are looking for a custom solution that needs custom parts.
not to mention the hole where a PSU should be in the machine unless you have done some custom mod
Be aware also that the longer the cables the greater the resistance. If you are going to be up against the limit of whatever PSU you are using, get the next size up in wattage.
YES if you DIY your cables that long ALSO get larger AWG cables. and another though, if your PSU gets kicked or just moved, it has the potential to kill the motherboard sockets, if not the entire board.