I would think it perhaps a bit early to worry about, or anticipate, the D7000's successor. I waited until the reviews and comments indicated all was well, and bought my wife a D7000 a mere six months ago.* It was one of the last few that were available in 2011, which effectively prevented me from acquiring a second one for myself, or as a back-up for my wife. (Yes, I had thought about fully or partially switching to Nikon DX digital, before I purchased my most recent Canon L lens and flashgun in early 2012.) Only in recent weeks have USA dealers been able to again keep the D7000 in stock. At the local dealer level, the available D7000 cameras sell within days, especially the few available as body-only.
A few new D90 cameras were still available from local dealers a mere few weeks ago.
*My wife uses her D7000 in her work, as a forensic investigator for the county medical examiner. The D7000 is a most excellent camera in the field, where relatively light weight, and some degree of weather-sealing, are desirable features.
Canon 7D2/7D/5D/40D/1D2N/M3; Nikon F6/D700/FM3A/1Dx/Coolpix A; Canon 40mm 2.8 STM, 135L, 50L, 35L, 50mm 1.8 I, 100mm 2.8L Macro, 10-22mm EF-S, 400mm 5.6L, 16-35mm 2.8L II; Nikkor 50mm 1.2 AI-S, 50mm 1.4G, 50mm 1.8D, 16mm 2.8D Fisheye, 180mm 2.8D, 100-300mm 5.6 AI-S, 45mm 2.8 AI-P, 14-24mm 2.8G, 24-70mm 2.8G, Micro-Nikkor 60/2.8G; Voigtlander 90mm f/3.5 SL II, Zeiss ZF.2 2/135 APO