I got the idea from diy that (i think) did one. I'm just looking for pics. It would be awesome to have an AK from the MOTHERLAND!!!!! The only difficult thing would be to drill a new hole for the gas block but I think a good smith would do it.
An alternate method is to tap the existing 90 degree port, and use a set screw to fill it in. Then zap the top of the set screw lightly with a MIG welder to retain it. By using a set screw, it prevents any weld material from flowing into the barrel which would then need to be reamed (not easy on a chromed barrel). Once you've plugged the existing hole, just drill the new 45 degree port (in a different location) and you're done. This isn't very difficult. The hardest part will be locating the new port correctly, and positioning/pinning the new gasblock.
If you don't have a welder, you can use Loctite #262 to retain the set screw. In this case you would probably want to stake it also (using a sharp punch) - this way the set screw would be 'mechanical' retained by the staking, and 'chemically' retained by the Loctite.