Good rundown Meneses!
Yes James, the euro and USA versions both have functional "street parking lights". It is a function which which has been preserved on even later Mercedes cars. I use the ones on my 2002 Mercedes SLK anytime I park along side the road at night.
Most often, as Meneses has noted, corroded sockets are the culprit. Sometimes they are left unhooked from the last paint job.
Yes Meneses, I am sure your flasher adaption would be quite interesting, as permanant or at least as an emergency repair till original can be installed.