I'm not aware of any after market articulated triggers. Sent you a PM earlier about a gentleman who can fit one to your project gun.
I tried to find a schematic/drawing of one on the net that I could post a link to, but have been unable to do find one, so far.
Beretta often fit them to their two triggered guns. Cole may have one he would take a pic of dismantled for you. Beretta or Cole might sell you one as a spare part & you could run with it from there. Warning: all on my Berettas are satin chrome finish, so that needs removing first, if to be TIG welded to another trigger. If just fitting the 'articulated' portion, then a non-issue.
As an aside, many seem to think that an articulated front trigger's purpose is to keep the finger from being bruised when firing the rear trigger. Not so, tho it may do so in some secondary sense. Most guns so fitted will have large trigger guard bows [think gloved trigger finger in COLD weather] and having the front trigger hinged or articulated allows a gloved finger choosing to fire the generally tighter choked bbl [back trigger] to move the front trigger forward w/o accidentally prematurely firing the back trigger from lack of clearance or sufficient room. I'm sure you know that, but others reading this may not, so thot I'd throw it in for whatever it's worth.
