Pro/Forums - Ultimate drilled water block?

I have recently gotten into water cooling and I decided that i am going to put a WC setup into my computer soon. I really am enjoying working on it right now, i have made the resevoir and really want to make my own waterblock so i began looking into drilled block designs and i came across one that looked very promosing. I would like to know what y'all think the performance on a block like this would be and what kind flow i will be looking at. Well i cant find a pic, but it is pretty much two 1/2" diameter holes drilled in each side of a copper block with a large number of smaller holes connecting them. I really think this would be a good water block, the only problem is that a copper plate has to be soldered to one side where the small holes are drilled. Is there anything wrong with this setup and are there any problems with drilling copper? Thanks in advance.