Paul Semenza, an analyst at DisplaySearch, has surmised in an interview that to beat the iPad Mini to the market, the second generation Nexus 7 may be unveiled even before Apple's higher-resolution device will be launched.
The iPad Mini Retina will possibly be introduced on the third or fourth quarter and will have similar resolution as the iPad 3 and 4. The present iPad is not as smooth as other contemporaries in the market. The Retina technology will double the iPad Mini's pixel density and will really improve the quality of display.
Semenza also mentions potential suppliers for the iPad Mini's display. He didn't mention any for the Nexus 7 but the device will similarly feature a richer display than the last generation. It might also feature HD technology as smaller tablets are somehow going in the same direction as the bigger tablets' display were improved markedly.