Ok, here’s what finally fixed it for me.
Son of Suckerfish uses left:-9999em to hide the submenu, and left:auto to restore it. Uses auto because of an issue with Opera. I ended up creating an ie6/7 specific stylesheet that just uses left:0px; to restore the submenu instead of auto. Seems that when I used left:auto, ie6 was shifting the absolutely positioned submenu all the way over to whereever I had my text-indent set to.
That seems to have fixed it for me now. There’s only 1 little residual issue with this fix. I have my navigation bar set as a div 980px wide, absolutely positioned. Inside that div, my UL#Navlist is positioned relatively. The list elements are positioned absolutely with respect to the parent UL, with each one receiving top, left, and width properties. The minor issue is that because there is empty spacing between some of these menu blocks, mousing over the empty spots between menu items seems to make the first dropdown menu pop up. The spaces are relatively small, and IE6 only makes up about 8 percent of our visitors over the last year, so I’m not gonna worry too much about this at this point.