Missing power cable for Bose Sounddock
Repair may the only solution.
The new power supply is only slightly different though.. If you don't want to spent the $100 to repair this, you could get the new supply and carve a notch in the top part of the square power input.. Looking at the new power supply, the top is a bit taller and arched but the same specs..
But the new power supply is still expensive. (I think $60+) So for an additional $40 ($100 total) you can get a new supply retrofitted on to the old input. It's worth it- you get a new 1 year warranty, and they put the new Apple dock connector on there (USB charge pin) as well as the power supply, so you can use current iPods as well as old. (Your SD currently won't support- iPhone 3G, iPod Touch 2ng gen, or iPod Nano 4th gen.. it will after a repair)