The one place I'd be happy to see D:OS2 material would be if that wizard/merchant from D:OS2, who left Rivelon to go planes-hopping in search of other forgotten realms... has a little shop in Baldur's Gate, and sells paraphernalia from his planes-walking adventures, including relics form Rivelon. That, to me, would be an acceptable level of insertion, because it can actually fit within the existing realms lore, while still being a hat tip to the developers and their past projects.
