No, there seem to be not so much information about Gutnish out there. Not much on the web and especially not in English. But most swedish sites are quite confusing too and a lot of people are misinformed.
There are some very good literature in Swedish, but the publications are mostly quite old.
Though there should be thousands of people that are brought up with the language. Either they spoke it themselves or people in there suroundings did. Gutnish people born in the 50’s or later also speak quite good English so it shouldn’t be such a big problem finding more information on the net directly from native speakers (in case anyone doubts my information ;-)).
Anyway, with this blog I hope to spread some basic information about the Gutnish language, both the Old and the more Modern one.