PCTechzone is reviewing a new heatsink from Thermaltake.  This one adapts to Socket A, Pentium 478 and your A64.  Take a look as they do pretty well with it.

“The POLO 735 is o­ne heck of a cooler. Those of you that have the Volcano 12 will love this cooler. The POLO is the Volcano 12, with a few well done changes.”