Okay, so 100% a scam. But – their plan is to get paid for a non-existent bike, and when the buyer comes to collect it...then what? Do they figure it would be their word against the buyers, and they will claim to eBay that it was collected?
Even with eBay being as crap as it can often be, I don't see that one working out for them - that's why the whole collection code thing was brought in (not that people often use it, but in this case the buyer could easily point out that the code has not been entered by the seller).
I suppose they figure it's worth a punt and if it fails they can just create another account (no doubt they already have lots of other accounts anyway).