I got a standard alder strat body from Northwest guitars that was actually one piece (advertised as two though). You would need to contact them to ask if they can provide you with what you want as I don't see swamp ash or contours among their offerings.
I had to do a good bit of work extending the contours - especially the ribcage one, as there was a lot less taken off than I needed but if they're willing to do it, I guess they would do it to your specs.
They're UK based too so, like buying something from the US, you have to count on customs and exchange charges, along with shipping probably, which add a lot to the real cost.
Alternatively, I had also considered buying a finished body from Franchin guitars in Italy. The prices have gone up since then as this was a few years ago, but even still it may be worth considering if they will add the contours for you and having it finished is of benefit.
I don't know of any other good alternatives although maybe you could find a manufacturer that does something similar and persuade them to make you just the body.