We have been building a Shopify extension that will allow Shopify store owners to easily (and pretty cheap) have an application in the Apple App Store, selling your products directly from the iPhone.
We are currently looking for beta testers that want to test out our service and give us feedback on where the service lacks certain features or just does not work.
Everything is quite beta, we are still adding features, fixing things, correcting spelling, etc. But if you would like to help us out, please let us know. You will need to give our app read only access to your store, so that the iPhone application can fetch products, variants and collections from your store.
Currently our example application is in the review process at Apple, but in the meanwhile you can contact us and we provide you with some more details.
We included a couple of screenshots of our iPhone application, running with a default customization.
You can email us at info@iosfy.com .