to find some stock a-arms. you could try ebay. or your local pull a part....
IMHO - i would put dually hubs back on and shorten some stock dually a-arms a couple inches. ( i think lock shortens them 1-1/2 inches..)
this would "push" the wheels back out and get the wheels away from the a-arms .
or..... you could buy some top arms and lengthen them out a couple inches and keep the 3/4 ton hubs..
:edit: you would also have to lengthen the lower arms as well...
here is a pic of his top a-arms. the previous owner cut big pieces out of the sides so the wheels wouldn't hit the arms.....
since this is a 2001 dually. is it supposed to originally have some tubular a-arms ?