If anybody else is interested in having some made, he can pretty much make to order / spec. I needed flat head nuts for new extended studs but with the correct shaft to locate the alloys I have on the 914 centrally. He has however made me ones with tapered heads for another car in the past too.
Dependent on requirements cost is circa £65-£95 (including washers) a set of 16 delivered (20 would cost more). This compares favourably to off-the-shelf options elsewhere (that in my case didn't fit properly!).
You can reach Bill Brighton on brightoncc@hotmail.co.uk, otherwise PM me for his number.