Christian-- your price seems expensive, and I wonder why. I'm currently writing to both Shepard's Life and "CBT Plus ECO" (not CBT) and they're offering about $200 for a 3 day 2 night horse trek to Song Kul for one person. CBT doesn't even respond to my emails.

Hi Mark,
thanks for the info. $200 sounds more reasonable. I wrote to both email addresses which I found on the CBT websites. I received a reply within a week with various tour offers (Song-Kol, Sary-Chelek, Karakol). All of these tours are priced around 500 to 700 EUR.
Therefore I was thinking of just showing up at places and trying to arrange stuff localy. As I am kind of short on time and it's almost off season, that might be tricky.
I will write to "CBT Plus ECO" as well. Couldn't find an email/ contact for Shepard's Life unfortunately. As suggested we could split costs on Song-Kol if our schedules fit.
Cheers,
Christian