Hub did one last year. Read about it here.
I do think the advantage is you can make it from one Luger not have to weld two together like Martz does. The other 45s are made from Scratch and are expensive. I love the Kustom Ballistics option. If I had one, it would be rust blued and strawed though.
http://forum.lugerforum.com/showthre...&highlight=GAP