This is what I'm working on, a bastar dized version of lozzmann's using 100mm PVC pipe and socket:
http://lozzmann.blogspot.com/2009/09/cokin-x-pro-filter-rig-mark-ii-nikon-14.html
Cokin products are tough to find considering they were in financial trouble and recently got bought over by Hoya/Tokina
May be awhile before product stocks recover
The universal ring has just about disappeared from any sale market ;p
If you're keen on filters however, can custom make from Formatt/Hitech; had a 6 stop delivered to me custom cut although oddly I've been sticking to using my welding glass instead
I like this idea.....I'll have to look into something like this for my 14mm Samyang.....
Cheers