Edit2:
What about the Exodus Knife. If there wasn't Rope Trick power in 4E now there is one.
And the Dust of Creation is a money making machine. Make a astral diamond (or a 25 pound block of astral diamonds which are 12500 ADs worth 125000000 GPs) and put them into a Pouch of Platinum to prevent them from disappearing.
Or what about creating residium and using that for making magical items?
The PoPP converts
normal coins and gems to platinum. Astral Diamonds created out of Dust of Creation wouldn't be normal, they would be temporary items that radiate magic. Residuum isn't mundane, it's the raw material of magic item properties. Dust of Creation can only create
mundane items.
So none of that would work. Realistically, even the village idiot shouldn't be buying fantastically useful or valuable items that
glow from a random adventuring stranger that wanders into town in a 4e setting. If he did, well, how much money do they pay for the position of Village Idiot these days? Very little gain for the risk that the VI is going to run off and show his friends or family what a great deal he got, and have them run you out of town.
It's too obvious what you're aiming for anyway, if you ask for those items.
In terms of money making items and sheer utility of items, I'm surprised people aren't making more out of the
Pouches of Shared Acquisition. These little items are incredible useful. Give one to your trusted NPC friend or relative from a decent-sized city. When you stroll into a distant town or city, announce, "Instant message and small package delivery to Waterdeep! No danger, no risk! 1 gold per message, 10 gold per small package!" Or set yourself up as a courier that can provide an instant reply to a message. The Duke of Anywhere wants to communicate with the Prince of Nowhere, so he hires you to deliver a message. You deliver it, and the Prince can scribble off a reply to the Duke and it gets there instantly. Half the communication and travel time.
Now, as for utility, say you're in a dungeon and you're in dire need of a potion. You slip a note into the pouch, maybe some coins. Your cousin or brother or whatever (who is probably fairly attentive to the pouch if you've been using it to make money with him) runs down to the corner shop, buys the potion, slips it into the bag, and you've just made a purchase from a big city merchant from hundreds of miles away, at the bottom of a dungeon.
Even without a trusted NPC, they still have their uses.
However, depending on GM style and opinion, any money making proposition in 4e may be moot, as I think that the DMG says something about taking money earned or made out of the total wealth a character should have. A strict interpretation means that one level 10 adventurer is worth the same as another, even if one is a cunning entreprenuer and the other doesn't pay attention to the coin in his purse. The Pouches of SA would still be amazingly useful, though. A group of quick draw rogues, each with a shuriken or other small equipment that has different properties, could chain the pouches together and share those weapons or items as needed even in the heat of battle.