sudo fs_usage | grep 'getattrlist[^@]*Finder'and then select the item you want to symlink to in Finder. Don't actually open the selected item, because the Finder will start to access stuff inside it (if it's a folder). When you select the item in the Finder, the Terminal window should now display at least one line like this (extra spacing deleted to save width):
15:45:08 getattrlist /.vol/234881031/3053977 0.000051 FinderThe last one is your target, so you can create the symlink by typing:
ln -s /.vol/234881031/3053977 myaliasThis link will stay the same even if you move or rename the target.
[robg adds: In my testing, I couldn't seem to figure out which of the several getattrlist items to select -- if I clicked a folder, for instance, I'd get about 20 lines of output, some of which were dupes, but others weren't. If anyone can clarify this method, I think it could be very useful.]

