Found a nicer way to do it that doesn't screw up your Get/Inspector box.

USUAL DISCLAIMER: Before you begin, make sure you have backups, and that you know what you're doing. You'll need ResEdit, QuickConvert, and the last comment in this thread.

Follow the instructions above, until you get to the part where you copy and paste the provided resources. You actually don't need them.

Two resource types need patching, the MENU and the Mcmd. The first one makes it look right, and the second links the commands (I think). In your copy of the Localized.rsrc file, add two menu items at the *bottom* of MENU #129, the File menu. (Adding to the bottom avoids screwing up the other items.) Add a separator line, then a submenu, Icon Size, linked to ID#139. This second MENU resource already exists.

(BTW, pasting in the provided resources would screw up the Get Info/Inspector items. The OS X Finder uses subsequent menu items to provide the alternatives shown when Option is held down. That is, Close Window becomes Close All when Option is held, but in the MENU resource, Close All is simply next in the list after Close Window.)

The Mcmd resource is a little different. Open ID#129, go to the bottom, and copy the last eight bytes, currently "00000000466E6446" in hex. That's four nulls and "FndF", which is the Find command. Just after these bytes, paste them in again. (BTW, the nulls are just the separator line.)

Change that last "FndF" you just pasted for "Isiz". The last hex bytes should read "000000004973697A".

Save, drop on QuickConvert, Quit Finder, and use the Terminal to copy over the old version. Make sure you have a backup first. Restart the Finder. Works for me, though I haven't restarted yet. Enjoy.