Alt[1] has isomorphic support but there are some trade offs such as you're unable to use actions on the server. But you can still keep your stores as singletons and have them be concurrent. I'm still juggling on different ways to tackle this problem to offer more flexibility. There are a couple of example apps sitting in the iso[2] repo which is an isomorphic helper class.

1: https://github.com/goatslacker/alt

2: https://github.com/goatslacker/iso/tree/master/examples