Is there a way for trade to take place that doesn't create incentives for this sort of concealment? Aside from large-scale market pricing of commensurable goods?

Isn't that what mechanism design is about? eg, a second-price auction is supposed to produce bidder honesty by the seller promising to concede the game of bilateral monopoly. Aside from reducing the transaction costs so that the sale actually occurs, one hopes that the honesty is a positive externality.