Yep. Custom always costs extra....and usually a lot more than was figured at the start of any project. Measure the drop on your rim v the stock one using calipers. If it's more than 12mm, you're on to custom made spokes. Less than 12mm, probably just a length issue (still custom!) and the head bends etc would work just fine as stock, but I'm not much more help than that for your situation. In the past I've re-cut threads with the correct die and cutting oil on stainless spokes and then cut them down and back the die off cleaning up the cut end. Lots of tedious work there. At least one day's worth. You can do the same with chromed steel spokes, but you need to have the chrome removed by a shop in sulfuric acid using reverse electrolysis...do your work with the die and shear....then have them re-chromed.