Microsoft wasn't the only missing belle from the Ultrabook ball. Three enormous manufacturers were missing from the party. Acer, likely riding the coat tails of their new-ish high-end machine, the Aspire S7, skipped the laptop part of the show. Dell was also an absentee; perhaps they were a bit busy stirring the pot of intrigue around their supposed anti-IPO. The real elephant out of the room though, was HP. The No. 1 manufacturer was completely silent on the Ultrabook, launching only a few wimpy AMD-powered machines. Youch.