This is a discussion of the 3rd Party gear and accessories available for the A99. The A99 (and NEX-6) depart from the Minolta-style hot-shoe that Sony inherited with Konica-Minolta to an (almost) ISO standard hot-shoe.
I am currently testing the Fotodiox Wonderburst HS8800 radio trigger with the A99. I will also test my Radio Popper kit. PocketWizard is sending me a PW3 kit with high-speed sync cable to try out as well.
In the lens arena, I have a Rokinon 85mm f/1.4 and will be ordering a Sigma 35mm f/1.4 A1 shortly.
Anyone else who wants to jump in feel free to add to the info!
Decided to order the Sigma 24-70 HSM Alphabet Soup in Sony mount from a local dealer along with the flash (got to support your local photo store if you want them to survive a give you great service).
While I know the Sigma is not the ZA2470, it has gotten some fairly rave reviews and is actually sharper wide open in the corners @24mm than the Zeiss (according to DXOMark) with almost no CA.
The flash to get is the HVL-F60M as it is the only TTL game in town for the A99. I briefly used Mikal's HVL-F58M with the adapter bundled with the A99 but found it a bit too wobbly for my tastes.