What sites provide a large selection of replacement bumpers for a car?
There are multiple sites that have replacement bumpers for vehicles of all types for sale. The most prominent are Car Parts Wholesale, Auto Parts Warehouse, and Westin Automotive.
There is a website that makes replacement swing cushions and canopies for patio swings sold at Costco, Wal-Mart, Target, Lowes, Sears, Home Depot, Wal-Mart, and other retailers. See links. They're made with Sunbrella fabric so they will last for many many years (Sunbrella awning fabric comes with a 10 year warranty). They have a good selection of fabrics. They seem to have a very large selection and cover just about every model.
Artificial selection (or selective breeding) describes intentional breeding for certain traits, or combination of traits. The way to breed pigeons with large beaks is to find pigeons with large beaks of both sexes and mate them and then not allow breeding for pigeons without large beaks. You may also be able to genetically engineer pigeons so that they have large beaks.