The old ladies bikes in-game are cute and their speed envelope seems realistic (handling is bad tho, steering is sluggish) and they work somewhat ok on flat grassland too.
But i feel there’s room for a new bike class, faster on pavement and even terrain, but slower in the rough.
So i want to see the recumbent bike in-game!
They have been around since the 19:th century and their aerodynamic properties make them alot faster than normal bikes, i can cruise mine at 30-40km/h with the same effort as i would use at about 20km/h on my old ladies bike.
also, since they offer a lower seating position, it would be easier to remain undetected while sprinting past enemies if theres bushes, cars and so on in between.
Anyone kan build them, i built mine out of plywood and old mtb parts, so its not unrealistic to add one to the game.
Off topic curiosa: my nickname is a short for “liggcyklisten”, the recumbent rider in swedish. 
The build blog for my recumbent can be found at www.liggist.se
(I think i may still have some CAD models of various 'bents if you want non-copyrighted models/designs to import)