It looks like the Wheelsmith XL 15 would be a great choice.
http://www.wheelsmith.com/
Jobst Brandt has posts from long ago that are very critical of the alternate DT Revolution spokes, which don't look like old DB spokes anyway.
Building a decently tensioned wheel with such spokes can be a challenge.
Joe Bender-Zanoni Great Notch, NJ
TP.C. Kohler wrote:
> Nothing is ever easy with this stuff, is it?
>
> Does anyone know of a good source for 15/17 db stainless spokes?
>
> Everyone has 14/17 but the specs for my '58 RRA call for 15/17.
>
> Peter Kohler
> Washington DC USA