By Daniel Eran Dilger

Published: 02:00 AM EST (11:00 PM PST)

Many retail partners sold out their very limited iPad 2 inventories on launch day, but a variety of well stocked Apple Stores ran out of many or all models as well after a launch extravaganza that maintained hundreds of people in hours-long lines throughout the evening.

In San Francisco, Best Buy sold out of its inventory right away, while Apple's own Stonestown store was out of stock within two hours of going on sale. Staffers there estimated they wouldn't have many tomorrow either. Apple's flagship Union Street store downtown ran out of WiFi iPad 2 models, but still had a stock of 3G versions for both AT&T and Verizon, at least of the 32 and 64GB variety, and only in black. It planned to remain open through midnight to offer remaining supplies to the hundreds standing in line

Store staffers plied the line (which for hours continued to stretch around four sides of the block back to the rear door of Apple's store) updating customers about which models were still available as they waited. One customer remarked he'd been standing in line at Best Buy for two hours before employees at that store finally told people in line that they'd sold out, noting with some frustration that he "knew he should have come to the Apple Store."

Lines for iPad 2 in San Francisco stretched longer than last summer's iPhone 4 launch, but Apple seemed to handle transactions faster. Another two dozen people joined the line on the opposite side of the block within a ten minute period after 7 PM, even after WiFi models were reported to be sold out.

One cafe, located near Apple's back entrance, sent out a waiter to chalk out a gap in the line of people waiting so they wouldn't block the front of the establishment. Apple had its own line management in place around most of the block, and had employed security guards to monitor the line. San Francisco police were also at the scene from about an hour before sales began, and remained though the evening.

Lines in New York City's flagship 5th Avenue store were also of record length, stretching around the block and then across the street to the adjacent block. Readers reported the iPad 2 line there being longer than any other product launch as well.

Readers noted early and long lines in a variety of locations, and also reported that inventories of iPad 2 had sold out in many locations, from Columbia, Maryland to Lexington, Kentucky to Dallas, Texas. Stores in the Los Angeles area, including Beverly Center, Century City, Santa Monica and Manhattan Beach, are all reported to be out of their initial supply of iPad 2s, while the Grove store is said to have a limited supply that is running out.

Stores are expected to get new shipments daily, but staffers said they didn't know what they would be getting. Report iPad 2 inventory in your location and we'll add it to our report.