The 30-pin thing is, I believe, because of the larger installed base and the availability of 30-pin-to-lightening adapters.

So a few products to look at:
1. Arcam's dRDock http://www.whathifi.com/arcam/drdock/review and a basic pre-amp or Cambridge Audio http://www.audioadvisor.com/prodinfo.asp?number=CADACMAPL combined with the PURE docking station http://www.amazon.com/Pure-i-20-30-Pin-iPhone-Speaker/dp/B0049MOK92 (or similar products from the page).

2. A Bluetooth/AptX pre-amp like http://www.whathifi.com/news/musical-fidelity-reveals-m1-sdac-preamp-headphone-amp-and-aptx-bluetooth with the PURE or other docking station.

I think a lot of the market will move to vendor-neutral streaming technologies Bluetooth/AptX rather than continue to build DAC/pre-amps that only work with Apple.

hope this helps.