I'll be honest and say that the brushed Space Gray aluminum looks off with the gold band. What would look better is shiny black chrome (Space Black) paired with a gold band.
That said, you seem to want to do it as cheaply as possible so you sound like a good candidate for one of those $99 DIY gold plating kits that you apply with a pen. Personally, if I'm going to possibly void my warranty I want it done right and go with a site that uses hardened gold that will not rub off. You get what you pay for.
For sure but I can't justify the added cost for SS, I'll make do with this for 1st gen, maybe in a gen or two I'll pay a little extra. I think this combo is kinda interesting/striking though so hopefully I'll be happy with it.
I'm not too worried about the warranty because it's only the band I'm plating, but I wonder how easy it would be to do it with a pen given all the little loops etc.
If I can only find someone with a bath then I'd happily buy the gold solution, they're pretty damn cheap it seems, and then all you need to do is clean the band, set up the bath and leave it for a couple hours - bam. I really don't want to pay a $100-150 surplus just for that.
I'll just have to try and find a local amateur or professional jeweller that has a plating bath.