If you are looking at RCL, they have a royal family suite (also known now as two bedroom suite) that can sleep 8.

The typical layout is 2 bedrooms with one clearly the master with its own bathroom, and another bedroom that sleeps 4 (2 lower beds, and 2 pullmans), and a sofa bed in the living room provides the final 2 sleeping spots.

These usually book very quickly since there are only a few on each ship, and pricing-wise, it is comparable to a grand suite for passengers 1 &2, with the additional passengers paying the 3rd and 4th passenger rates.

Often times it is cheaper to book 2 separate cabins, but since this is a suite, you would get suite perks, too.

Good luck with your planning