This has been bounced around in threads not linked to any team. Just general discussion. Consensus seemed to be no more than a third unless you manage to get teams into a bidding war.
His value prior to signing with Montreal is meaningless. He's shown a commitment and attention to details at both ends of the ice while in Montreal. Things didn't work in LA. They work in Montreal. They can work elsewhere.
If he'd been with Montreal the last couple of years, was producing at a rate similar to what he is now, and the team was still out, teams would offer a fair bit. Regardless of his age, guys with his skills that hit the trade market fetch a return. It's only diminished because he's been with Montreal for a couple of weeks.
From a Montreal perspective, the prudent thing to do is trade him at the deadline. Depending on what Caufield chooses to do after this season, I'd consider bringing Ilya back on a one year deal. He's fit in well, likes the group, has gone above and beyond (taking the whole team out to dinner), and I think he'd be a good offensive mentor for some of our young players.