There's the free Wastebasket that works like an alias. You can download it from versiontracker.com. It allows you to put the trash can on the desktop, as in days of yore. It links to the real trash, but the icon doesn't change when anything's in it.
However, you could put the Wastebasket (you can rename it) in any folder, then drag it to the dock where you'd end up with two trashes. Since both would be in the dock, it wouldn't matter that the Wastebasket icon doesn't change.
Another app, Bin-it, shows up at versiontracker with the search for Wastebasket. But it constantly runs in the background (and it's nagware).