i'm looking for front cones for my 2007 shimano 105 wheelset (straight pull spokes). the hub says wh-5500.

I just need the cones but, according to the exploded view on shimano's website shows the cone as part of assembly/part # Y-4CF98020 (and wheelset model wh5600 instead of 5500).

2 bike shops haven't been able to order these cones. the last shop said they contacted shimano and they don't make those cones any longer. any ideas on where to find replacements?