I've been using KMC e1 EPT chains on my singlespeed bike and now on the Rohloff. Chain is fine, except for it's durability - it elongates to 0.75 after around 1500-2000km only.
Best way to make your chain last longer on a Rohloff is to stop measuring it
I have three of the non EPT versions of that chain in use, 3,000, 5,000 and 9,000 km, I have no intention of changing them anytime soon. I understand the principle of changing the chain to prolong the life of other components, but on a SS/IGH it doesn't make economic sense for two reasons. First, the shifting doesn't deteriorate and second you're likely to spend more on chains than save on components. I haven't had a chain let me down yet, I've had a few "stretch" so far as to need a link removed and I've worn a few sprockets/chainrings out. I've yet to reach 15,000 miles on a chain, but sometimes I've changed close to that as a precaution. This is the advice in one of the Thorn brochures, possibly "Living with a Rohloff", wear all three out together and it'll be trouble free.
That Wippermann does look the business, if I hadn't stocked up on the E1's (I bought 4 when they were on offer and that might be a lifetimes worth) I'd be tempted to give it a try. Please do report back if you do.
I don't have any 1/8th experience, but I know it's possible to run them on a Rohloff, with the right chain and sprocket.
There's also the theory I read on the Sheldon Brown website, that running an even number of teeth and keeping the chain in the correct phase, stops the chain from wearing the chainring/sprocket. I haven't tried it.