The only issue I have with seats for lift trucks is that the seat frames seem to have been designed as if they are going to be placed on a table top, with nothing behind the seat tracks to obstruct the tracks or seat when trying to adjust for increased leg room.
The problem is that most lift truck OEMs now have a "bowl shaped" hood, or bonnet that the seat is mounted onto.
The bowl shape is apparent more behind the seat due to the fact that the radiator (on ICE powered lifts) is higher than the top of the hood where the seat mounts.
Because most seat frames just seem to come straight back and end right above the rear end of the seat tracks, the bottom rear edge of the seat and the end of the seat tracks encounter the bottom curvature of the hood in that bowl shaped back end of the hood, severely limiting how far back the seat can actually be adjusted.
This is a real problem for operators who are tall/long legged.
On some of our trucks we use an after market seat made by Sears Manufacturing (not Sears-Roebuck) that addresses this issue cleverly.
The seat we use made by them is a one-piece, steel stamping comprising both the seat bottom and the seat backrest.
The stamping is curved where the rear of the seat bottom turns upward to form the seat backrest.
This curved configuration cooperates nicely with the bowl shape of the seat cavity of the hood and thus permits the seat to move back further than can be done with standard OEM seats.
I doubt that extra leg room was their goal when designing the seat, but it sure does work well to give about 2" more leg room than the OEM "square frame" 2 piece seats.
The only drawback with these 1 piece, non folding seats is that they cannot be used easily on an LPG truck unless the LPG tank either swings out of the way, or tilts back to allow the hood to be raised for maintenance.