Apple's (AAPL) iPhone 5 supply is catching up with demand, at least in the U.S., analysts say. Next up for the hot-selling smartphone is its debut soon in China. Nightly checks of 100 Apple retail stores indicate that iPhone 5 supply for AT&T (T) and Verizon is improving, Piper Jaffray analyst Gene Munster wrote in a research report Friday. It may be another two to three weeks before there is consistent availability of Apple's latest smartphone