There is detailed instructions as to how to remove the instrument panel on a great site. Go to: http://hsb.baylor.edu/html/easley/autofaqs/main.htm
Then scroll down to electrical and click on the article about fixing clocks. I'v had the panel out of my 240 and my 300 SD without removing the wheel.
Please let us know the details on the success or failure of your LED experiment. It should work!
'85 300 SD, 165K-Sold
'88 300 TE, 165K-Sold
'64 Porsche 356C Cabriolet
'86 560SL 124K Miles
'94 320E Wagon, 74K Miles