What 2 up to buy?????

Ok, i have a 1 up 800 p tek, love it.
i bought it with intent to ride 2 up with my girl, so i got a 1+1 seat, set the suspention up for the weight, and it SUCKED!!!!!!!!!
needless to say i bought her, her own sled.

now heres my question.

My Dad, almost 60 yrs old, but very very active, rides harleys, go fast boats ect ect so he is no old man. he has a condo in NH, and is thinking about sleds.

now my mother is also very active for almost 60, she rips on my quad (z 400) rips my Fathers Z06 vett, no joke kind of people. (and fun as sh&%)

anyway, he would like 2 sleds, an 800 for him, and a 600 or 800 for my mother, however, he does not have room for 2 sleds. so he is thinking 2 up highest horse power possable. he is a little scared on the 2 up thing tho after my experiance.
so im wondering, what would be the best sled for him, and is it somthing they will enjoy, or should he say screw it, buy some sort of shed and get 2 sleds.
pics would be great as well