A City Council panel has approved plans for a $1 billion Seattle Children's Hospital expansion. Children's had warned that it would consider moving outside Seattle if it couldn't proceed with the expansion. Construction on the 20-year expansion, which would add up to 450 more beds, could begin in 2011. As part of the compromise Children's also agreed to cut 275,000 square feet from its planned expansion of 1.5 million square feet. The campus now has about 900,000 square feet, the Seattle Post-Intelligencer reports.