I dont know of any preference file that can do what you requested but you can try the following...
Go to ~/System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/Resources/HIToolbox.rsrc and make two backup copies of this file.
Drag one of the backup copies onto QuickConvert, the app will launch and nothing will happen.
Launch Iconographer and open up the copy that you dropped on QuickConvert.
Scroll a third of the way down the dialog until you find icon number -20789.
Double click on this icon and delete the mask (the black and white version of the icon) and the icon (the color version) but do not delete the whole family.
Save the file and quit Iconographer.
Drag the file onto the QuickConvert icon again, again nothing happens. Now quit all open apps except for the Finder.
Replace the original HIToolbox.rsrc with the edited one and restart the computer.
Now, since the finder cannot find the data for the alias badge, it should not display it. Also, make sure you keep the original file in a safe location just in case something happens that you need to revert to the original settings.
An easier way would be to get the latest version of Iconographer (The one that runs natively in OS X) It allows you to edit icons right inside that .rsrc file. As well as many other files. Do in Root, though.
BE CAREFUL whatever method you use. Backup ANY file you edit.
I think the starter of this thread didn't want the little arrow to appear in any alias icons. Using Iconographer or some other graphics utility only changes that one icon, but the arrow still reappears when you make a new alias file.. I think Hisaoki wanted to make sure that this arrow never appears, and martinatkinson has the right way to do it.
I've ALWAYS hated that icon. I loved when the Mac OS used italics labels to convey aliases or in the BeOS where they were underlined. (I like the BeOS method more for some reason) I found a cool Control Panel for OS 9 to remove them and make the text of aliases how you want them to, but no X equivilant is available yet. Someone needs to create a Preference Panel for that.
I still don't get why Apple decided to take that stupid Windows feature. There are many other Windows features I would LIKE to see on the Mac OS.. The alias icon was not one of them.
Hopefully someone will figure out how to change the labels formatting and I will be happier.