The fact that the Beckhams didn't sue her tells me that she did sleep with him. I've always believed that she was telling the truth.
You've heard of the Barbara Streisend (sp!) effect right?
Suing would have kept the story in the papers for even longer - instead by keeping a dignified silence on the issue the only fame Loos has is that a few people on the internet are discussing how she once did something with a pig - and if it wasn't for Sharon Osbourne would we even be doing that?