I like the red seats too. I agree on the steering wheel. Personally I'd go with one of these moto lita or Derrington knock-offs. They look just right in a 356 and will adapt easily to your hub. I am also a fan of the plain 4-spoke "sprint car" style wheels. which are about as blingless as they go and (see below) would probably bolt right up.
Two-bar banjo style wheels are getting pretty dear. Someone on The Samba had an early Beetle wheel listed recently for like $500, I think. And then there;s the matter of matching it to whatever you have now.
As for adaptors, the 6-hole ones like yours are either Momo or Nardi (the spacing is very close but not quite the same, as this adaptor illustrates). Yours is probably Nardi. Most wheels on VW-based kits will have the ubiquitous early 3-hole Grant mount underneath that (as that adaptor illustrates). So when you get an aftermarket wheel, you tell them what you're adapting to: either the Grant 3-hole or your original column, which you will have to pull the wheel off to be sure what it is. Once you know what you have it's usually a simple matter to adapt virtually any aftermarket steering wheel to the hub.
BUT: If you're hankering to affix an original equipment wheel, you'll likely have to do some work. Some are splined. Some are keyed, and very few manufacturers' wheels will fit straight-off on anything much else than what it was built for.
All that said, almost anything can be accomplished if you have money or a welder. And sometimes you get lucky and don't need either one. I do recall reading about an enterprising VW bus owner adapting what he thought was a late '40s Ford banjo wheel to his ride. Just took a little filing, as I recall.