Linde AG could offer at least $3.4 billion to buy Lincare Holdings Inc., a report from Reuters said. Lincare (NASDAQ: LNCR), a Clearwater-based oxygen provider and one of the largest public companies in the Tampa Bay area, was not available for comment, the report said. Linde is a German industrial gas producer and is the leading bidder for Lincare, Reuters said, citing the Financial Times Alphaville blog. France’s Air Liquide SA and an unnamed private equity bidder also may be in the running…