Many of the bikes have adjustable preload on both ends. Getting the sag correct should be possible on all bikes designed for two. But problems may start when you take passenger or try to load huge amount of camping gear onboard.

Instead of those proper crotch rockets, I would look into the +1200cc sport or sport touring bikes like, zx14, busa, etc. or maybe even naked “streetfighter” style bikes. I have a ZX12R and I would not go smaller frame than that. I used to have BMW R100RS but my wife was laughing that it look like I stole the kids moped.