The log sounds fine to me. It actually sounds like a good alternative for chewing. By pine shavings, I would guess they just mean a processed, compressed wood product, rather than a solid chunk of wood straight off a tree. I've been using shavings as a bedding for as long as I've had rabbits (12 years) with no issues.
If you'd rather not use the log, why not bring in some branches from outside or get some pieces of untreated lumber for them to chew on? It probably doesn't have to be in a log formation to entice them. LOL And pine is a softer wood...they'd probably prefer hardwood anyway.
ETA- Wow, didn't realize this thread was already pages long. Nevermind- I'm sure this is old news by now.