Actually (depending on RP rules) I may know where you could buy one.
(If RP rules allow); A friend may have a hack job of a 240 lying at my garage (Not based on anything in particular, just a build of 240 I had as a save car in-game for a while, that combined many different styles; drift, time attack, shakotan, etc).
(If RP rules don't); Hope you find one, also I sort of want one.
Added 2 minutes later:
(If so); It's cream. And Black. And Red. And primered on some panels. With a spoiler on the bottom of its rear bumper. And a Diffuser. And some random wheels. And a blown SR.
(If not); It'll appear in the RP and you'll see it.