Sunstreaker wouldn't count as a 'new license' though. It'd still be under the current Lamborghini license.
He also seems like a less likely choice. Remember, his G1 toy was only released in Japan in one gift set, so he's not as big there as here. He was even sometimes replaced by Red Alert as Sideswipe's brother (or the early mention of them being triplets).
He just doesn't seem someone they'd rush to do at this stage.