There is a tandem-specific version of these wheels, but it looks like neither Spinergy nor House of Tandems (the Spinergy tandem distributor) has any info about them on their web sites.
AFAIK they are available in all the usual tandem hub options. Ours will be dual-disc with a 145mm rear hub and DaVinci disc spacing (25mm offset instead of 15mm offset). I forget how many spokes they have but I just sent an email to H.o.T. to inquire about that and will post the answer when I get it. I've also asked DaVinci to weigh the wheels when they arrive and I'll share the results here.
<--EDIT>The tandem full carbon clinchers are 24 spokes front and rear and built on tandem-specific hubs. The claimed weight is just under 1,600 grams. I'll should have a real-world weight to post in about a week.
<--/EDIT>
The tandem wheels should be heavier than the single bike wheels due to higher spoke count and wider rear hub, and they are $2,000. So they probably weigh at least as much as the Rolf Carbon and the price difference is not quite as big as you thought from looking at the single bike wheel price.
I'm a big fan of the ride of the Spinergy PBO spokes. The difference in ride quality over small cracks in the pavement is very noticeable. The Hadley hubs they use are super easy to maintain and should a spoke break they are easily field replaceable (even on the drive-side of the rear wheel). Like any wheels they can have issues... some friends of ours had cracks start to develop in their TX-2 rims and switched to Rolfs. I had a bearing issue with my TX-2 rear wheel but House of Tandems replaced the wheel at no cost (they even covered the shipping).
So the Rolf wheels are probably a bit lighter and they are more expensive. They have center lock rotor mounting which I would consider a plus, but not a big enough plus for us to select them over the Spinergys. I know there are a lot of riders who have had great experiences with Rolf wheels and you'll probably be happy with either choice.
I'm just wondering how long I can hold out before I
need a set of Spinergy FCC 4.7 (the deep 47mm version of these wheels).