Thanx guys for your answers, Due to lack of space I dont really have an option to make such a large machine or it would take up all the floor space!

Guys just a few more questions which have arisen on my quest:

Someone mentioned a waterpump. What is this and why would i need it?? I assume its to cool the material down maybe??
also am i right in thinking i need 4 different ballscrews. two on the long side of the bed, one on the width and one on the height. does this mean i need 3 different sizes? how do i know which sizes to get??

I have come accross a cnc bed which sucks the material down. This was on a ready made one. is that expensive? also is it a necessity?

On average from the plans how long should it take to make the machine?? (approximately)

Thanks all