Bladed spokes

I'm in the process of putting together some track wheels using some Phil Wood hubs and Reynolds DV46 rims. I'd like to use a wide bladed spoke in them - radial front, 3x rear. Due to the deep rim section I need fairly unusual spoke lengths - 249mm for the front and 276mm for the rear. Because of the internal nipples on the Reynolds rims I need a 2.0mm threaded spoke. Madison only have a few odd lengths - normal 700c lengths ~294 - 300, and Chickens don't seem to bring in the CX, only the CX ray. I could go to a CX Ray or aerolite, but for two reasons I want to use a full width bladed spoke. First because of the stiffness as they are for track wheels. Second because the hubs are slotted and it would be a bit odd not to use bladed spokes now I've gone to the hassle and expense of ordering slotted hubs...

So - any guidance on where it might be possible to source suitable spokes or possibly suggest an alternative would be greatly appreciated!