Further options include the aforementioned extra row of seats and a retractable tow - bar. (evo.co.uk)
This keyboard is almost exactly the same, except for a few different buttons as well as a whole extra row of keys at the very top. (lovemyfire.com)
There is a great programme called Plant a Row - Grow a Row where people add extra rows to their vegetable garden and then donate the produce to their local food bank. (treehugger.com)