I'm also in the camp that believes bidding will happen with vp's. As others said, debt could be broken with power gainers, and bidding debt at the start of the game could work but it sounds kinda unfun. But who knows. A landmark that dishes out vp's for debt at the start of the game wouldn't be unbalanced, but, again, will it be fun? I mean, there's a player that won't start playing for a while, I'm not sure I'd be thrilled.
Anyway, I'm more interested in knowing what we'll be bidding for. The right of selecting first a unique card from a pool at the start of the game? The same thing at some key point of the game?
As a famous game designer once said, it's the goal that's important, not the bidding.