Another mod of amazing Duplo Bumper Car by satoer. Not sure if it is will be useful for you folks, out there because I bought spare parts in local shop. But I guess, what I savaged spare parts from was a generic chinese LED-lamp (swan-like) and it could be sold worldwide.
Anyway, this model should accomodate for similar parts, which should not exceed 36 mm in diameter of the lower part and 15 mm in height. Bottom should not be thicker than 1 mm.
You will also need soldering iron and basic soldering skills to succeed.
Solder LED to wires
Remove LED from original place and solder it with wires around 3 cm in length.
Glue battery compartment
Glue battery compartment to the bottom of the car.
Assemble car as usual, but make sure LED is placed in one of the empty spaces to the left or to the right from battery compartment.