I have been asked to recreate a Vans shoe cake like the attached picture but colored like the multicolor portion of the logo on the tshirt - not checkerboard.  Any suggestions on how best to achieve that?   I have never airbrushed a cake before so I'm looking for a suggestion outside of that.  However, I'm not opposed to learning and even buying some equipment if needed.  The cake is actually a post from here on Cake Central :)  TIA!!

You could maybe handpaint it if you were very careful but I think airbrushing is going to give that nice smooth colour graduation the best.

I would suggest having a few practice goes first though   :)

I've also got a chart somewhere that tells you what order to do the colours in so that the overlap turns into the next colour you want (I hope that makes sense) - I'll see if I can find it for you if you need it.

Although having a second look at that logo I don't think you'll need the chart with a gajillion colours, looks like just starting with yellow, add a smidge of red for orange, then more red for red, then a little blue for purple, then just blue.

This is definitely an application that lends itself to airbrush work, but it would be a big investment for one cake.  Wilton makes spray colors that work well to give a similar effect and it could be done by dry brushing powdered colors, but probably not as smooth.