I figured I'd follow up with this issue in case anyone in the future ever has the same problem. I managed to get my hands on an electronic copy of the ETM (Electrical Troubleshooting Manual) for the W126 and it provided all the diagrams I needed to isolate and find the source of the mysterious Fuse 11 popping.

After studying the diagrams and figuring out what Fuse 11 controls, I was able to rule out the interior and instrumentation lighting since the fuse did not blow with the light switch in "L" standing mode, but did in "R", "Park" and "Head" positions (see diagrams for switching arrangements). This led me to narrow it down to wiring or bulb holder in the right front parking light or right rear parking light. (Circuit 58R). Pulling the plugs and probing the connectors showed the wiring (grey wire) coming up to the front right parking light is grounded. I later traced this to a chafed wire behind the false firewall.

I've colored the diagrams and am attaching them to this reply in case it ever helps someone else out in the future. Very frustrating!

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)