I think the WM9 Sub is actually very nice. It has really awful bracelet & SELs, and some problems with the bezel... but it looks fundamentally correct, and it's a great base. The crystal/rehaut combo is the best I've ever seen.
I don't have a Sub/SD rep at all right now. I'm quite sure there's something happening regarding the 16610 soon. Just a "hunch".
But if someone REALLY wants a 16610 rep now, I'd go for the route that L-Dizzle suggested. It makes absolutely no sense to put $500 on a rep, which will be updated and improved... rather sooner than later.
PS: Stephane is right. SSD is ok. I'm not saying it's crap, but it's nothing special. I'm really pissed off that the factories screwed up the thing what *makes* the Sea Dweller: Amazingly thick front rehaut. Pissed off because I waited this watch for YEARS... I really wanted it to be great. For me it's nothing more than another wasted opportunity, once again.
I found it really strange that the membership was so willing to forgive and ignore all those stupid flaws on it... although it was advertised as 1:1 replica. It was hyped a lot, and I'm sure it sold a lot.
With a little effort and consultation from our senior members it could have been awesome. I don't know why they always screw up something important with the Rolex reps.