Why are do you think the 290mm shocks are too long? Is it because the crazy rear fender clearance? I think hobbit rear fenders just mount like that (aka ugly).
I think you might better off mounting it a la Neil Burgess:
(can't find a good picture)
or rocking the Simon Earley chop that makes it flow nice:
If it has nothing to do with the fender then nevermind.