In another campaign [Iron Gods], I'm currently playing a...
Spoiler:
Go ahead and try it yourself. :)
machinesmith [see Louis Porter Jr. Design, Inc.] and I thought it would be interesting to swap out Varl's expert level to a machinesmith level taking the mobius suit as his greatwork. I'd to rearrange some stats but all in all, it seems to be a nice choice.
Have fun with your Hell's Rebels campaign and let me hear if you any suggestions about the variant class level.