I've finally updated sd_DynamicAreaLighting to take advantage of alpha transparency, but it's actually much more interesting than a simple icon change. You can now use your own custom darkness icon for the overlays.
The coolest part is that you can decide exactly how many shades of darkness there are in sd_DAL version 10. The old sd_DAL had 4 basic shades of darkness. Now you can increase or even decrease that number to match your custom icons.
Compile the library in BYOND 4.0 or greater to play a demo with the new features. You can change the darkness icon between several demo icons using the "dark icon" verb.
For those of you who absolutely refuse to update to BYOND 4.0, don't worry. You can still use custom icons and shade counts without being forced to use BYOND 4.0 and transparent icons. The demo even compiles in older BYOND versions and shows developers how to selectively compile code based on compiler version.
Hope you all enjoy it!