Since posting the Nexus 7 mini review, I've gotten a lot of emails asking about whether USB-OTG for storage was currently supported or would be supported in the shipping software load. I've done some asking around and believe I have the final word now.
USB-OTG is indeed supported on the Nexus 7, however as anyone has used USB-OTG knows, whether peripherals or devices work is a function of the host OS and drivers. On the Nexus 7, using a mouse and keyboard is supported, and I saw Google using an Ethernet to microUSB adapter with the Nexus 7 (which I borrowed for my Galaxy Nexus) as well. Unfortunately mounting USB storage natively is not supported on the Nexus 7. Hopefully rooted users will be able to use StickMount with the Nexus 7 and make this work. In addition, MHL is not supported on the Nexus 7, which isn't very surprising since adding MHL requires another package and would increase BOM cost.