Call a concrete coring company to drill a 4" hole in the wall a possibility? Maybe the same cost as the piping materials/vent fan electrical etc.. If not a possibility I think I would go with option #2 thinkg the 4' rise is for sure going to allow lint to fall back into the 90 and be a possible fire source at some point.
Get a hold of Jason Buffalo on here or his website and see if he has a thought.
http://buffac.com/