Placeholders for white iPhone 4 units have started to appear at both Best Buy and The Source retail stores. Engadget reports that a placard listing a 16GB white AT&T iPhone 4 unit for $599.99 off contract—the same price as the black model—was spotted in a Houston-area Best Buy, while listings for both 16GB and 32GB on-contract white iPhone 4s on Bell were spotted at a The Source store in Canada. Evidence pointing to a near-term release…
