If you don't like the K70s there's also the Dunlop K81s with a true rear tire. Hedenau has some that are a bit more expensive. And don't be afraid of lower price Asian brands like Kenda, IRC, and Shinko. They get good reviews and have loyal followings.
And people on this forum have used the listed front tire, say, 100/90-19 on the rear? Or 110/90-19?
Which one are you asking about?
Since you were quoting me before the question let me point out that the only one I suggested using the front on the rear is the K70 3.50-19. The K81 comes in 4.10-19 REAR. The other brands all make appropriate 19" rear tires.