I'm using the Octovo Solis being sold for the K3/KK/K4 on my Touch. It's not a perfect fit--in fact, I contacted Octovo before I bought mine and they're working on a new fitting piece specifically for the Touch that sounded like it would also be made available to current users. But it's a pretty good fit nonetheless, hasn't scratched my Touch, and is hands down the best reading light I've owned. And I've tried several over the last three years. I'm even pickier about lights than I was about cases...and I went through six or so of those for the K2.
The only thing better would be the Amazon Lighted case, but I no longer use cases, only sleeves.