Manufacture your own brand "approved" cabin luggage, a snazzy orange colour perhaps, or decorated with fine looking harp. Only this particular brand of luggage will be allowed into the cabin. All other types will have to be checked in and carried in the hold (at a charge of course
Lufthansa have had cabin-approved own logo'd luggage for years. The Titan flight bag and trolley case costs €129 or there's the Rimowa laptop bag and trolley case for €439...
My particular hate is 'aeroplane hikers' - people with large rucksacks which they insist on wearing whilst boarding.
The experienced business traveller will know not to select seats in row 1 (or row 2 D-F on some types) as there is nowhere to put your briefcase under the seat in front. Likewise, the front lockers are often full of newspapers, perhaps some CC luggage and some demo equipment.