I went to www.billyboyd.net to see if there was more on the announcement that he can't make ELF, and saw this; apparently it's more recent than that announcement:
"The Flying Scotsman
billyboyd.net are delighted to announce that Billy is starting his next project, The Flying Scotsman. The film tells the story of Graeme Obree, the famous Scottish cyclist. The film also stars Jonny Lee Miller and Brian Cox.
Details are sketchy at the moment but we'll keep you up to date with info as we get it."
Hmmm... swimming... biking... let's hope his next one is surfing! *S*