If you look the textures of some standard race cars you can see some updated logos in low-res textures. They did it about a year ago, after the shader update. If I remember correctly you can see them in some LMP, DTM cars and the red NSX LM.
My PS3 has 250gb. There's enough space here. I'm not saying they must do it, I'm saying they can do it and there's much less drama involved of what you are thinking. They already know how to handle different shaders for different effects in the same car, (matte, chrome, gloss, etc).
Basically, from 2006 to 20?? for a user interface, that's quite a record.
PS: No, I'm not saying they have to convert all standard textures to HD. -.- tornado facepalm.
Technically speaking there's nothing stopping them, which means a livery editor it's all about creating a user interface.