Whatever you decide to do I would be quite harsh on the individuals involved. If they get away with it then they will soon be planning there next heist, unless your happy for the campaign to head in that direction.
I feel that magical item shops either should be so secure that breaking into them isn't worth the hassle or need to be backed up by a powerful organisation. The temples of the gods of magic and trade may have an arrangement, or the local thieves guild may have been collecting protection money from the shop, and now need to keep there side of the bargain or lose face.
Also, what has happened to the body of the gnome? If the vampire spawn are intelligent they might be curious as to what people would be doing outside at night when its so dangerous. Assuming there is some mastermind behind the vampire spawn the gnome might be raised as unliving and tell the bad guys all about the party, and there new haul of magic items that might disrupt the BBEG plans.
As to what could be in treasure i would have mainly utility or entertaining items, the kind of things that local merchants or nobles might buy, i doubt most magic item shops make there day to day trade out of magic swords.
I'd also be tempted to throw in an item, like a rod, that allows you to touch 7 items and then for the next 7 days you can use the rod to act as a compass to any of the items. Not only does this item have plenty of uses in the kinds of conviluted plans players love to come up with but it should worry the players that the owner of the shop might have another of these rods and could track them very easily.
Though i'd throw a few nice items in as well or your players will definatly feel cheated, especially one item that everyone in the party will want just to get them arguing between themselves.
I feel that magical item shops either should be so secure that breaking into them isn't worth the hassle or need to be backed up by a powerful organisation. The temples of the gods of magic and trade may have an arrangement, or the local thieves guild may have been collecting protection money from the shop, and now need to keep there side of the bargain or lose face.
Also, what has happened to the body of the gnome? If the vampire spawn are intelligent they might be curious as to what people would be doing outside at night when its so dangerous. Assuming there is some mastermind behind the vampire spawn the gnome might be raised as unliving and tell the bad guys all about the party, and there new haul of magic items that might disrupt the BBEG plans.
As to what could be in treasure i would have mainly utility or entertaining items, the kind of things that local merchants or nobles might buy, i doubt most magic item shops make there day to day trade out of magic swords.
I'd also be tempted to throw in an item, like a rod, that allows you to touch 7 items and then for the next 7 days you can use the rod to act as a compass to any of the items. Not only does this item have plenty of uses in the kinds of conviluted plans players love to come up with but it should worry the players that the owner of the shop might have another of these rods and could track them very easily.
Though i'd throw a few nice items in as well or your players will definatly feel cheated, especially one item that everyone in the party will want just to get them arguing between themselves.