Buy the 911 for sure. You will have infinitely more fun in it than in the Unimog; it is at least three times as fast depending on the model chosen and there are only two small seats in the back. So, as the kids get older, you can escape the house and go enjoy driving in your Porsche
EDIT: Charlie, what do you think your crawl ratio or travel speed would be in your lowest working gear? I have seen some pretty low and also witnessed Toyota's Crawl Control being used to rescue a fairly well bogged Tacoma. Slow speed is where it's at for serious off road work. You have more time to react, significantly less abuse to the trail and the truck and no shock loading or flying parts should something go pear shaped.
EDIT: Charlie, what do you think your crawl ratio or travel speed would be in your lowest working gear? I have seen some pretty low and also witnessed Toyota's Crawl Control being used to rescue a fairly well bogged Tacoma. Slow speed is where it's at for serious off road work. You have more time to react, significantly less abuse to the trail and the truck and no shock loading or flying parts should something go pear shaped.