CL, can't you bend the rules just a little? The Lange 1815 in Pt/silver would be a great addition to that set, but it runs (I think) at 21,600bph. (If memory serves, you may have a couple of 1815's already).
A while ago Suitbert posted an article on some of Christian Klings' watches, one of which was a beautiful time only piece with teardrop lugs and a manual movement that looked as if it might be slow beat. That particular piece had a black dial, but from the article one gained the impression that Mr Klings would be amenable to a commission request. A little off topic, perhaps: the Klings tourbillon cage is beautiful to behold (even if only in photos).
The Vyskocil V-35/40-01-A runs at 19,800 A/h and is available in Pt or WG. Initially the dials were offered in black or white. Not sure of the position currently: perhaps silver might be an option on request. Presumably the power reserve would disqualify this watch from your themed collection. It would be nice to have anyway, though, wouldn't it? ;-)
Cheers,
pplater.