Vector makes a fine semi RPD that is nearly perfect. The stock angle is slightly off. You can still find them on the net if you look hard enough. Beautiful guns. As for the RPK, they use two types of drums. The Chicom drums you load from the rear while the Warsaw drums load from the top. The Arsenal RPK is one of the most beautiful guns I own, and I own a bunch of different AK's.
http://img511.imageshack.us/img511/3...lpc1jx1.th.jpg
And I also agree that if money is no object, buy them both!