Okay, I have googled around for this, watched some videos and I still can't manage to beat this one. Here are some of the thoughts I've had, perhaps somebody could confirm/disagree with any of them?
1. I have a feeling that in the past gold piles were giving more money on average. I got this feeling from watching videos, they had even some +7's there if I'm not mistaken. I usually get 2-4. Is this true, have there been any changes there, which could make some advice given in the past more or less obsolete?
2. Advice goes in the direction of Thief being the best choice because of 33% more items on the map, meaning 33% more gold. However does this mean that there is also one extra shop in the dungeon? Is there a race/class that is preferred for this mission?
3. Map selection. Is there any map that is better than others when it comes to beating the Dimensional Dealings?
4. Preps. Obviously Black Market is the choice, anything else that I had been missing?
5. So far there has been one dungeon where I came 1 gold short of being able to buy every item. However since then I hadn't come even close, sometimes missing 25 gold. I have a feeling that it's much harder lately, because of better items that I had unlocked. As a consequence those better items appear in shops more often instead of items like spoon. Is that how it works and can I do anything to influence item selection in the shops?
5. Obviously something like Gloves of Midas would have made this mission much easier. However at this stage I find it impossible to beat the last boss in the challenge. Is this the way to get the Dimensional Dealings done or is it possible to beat it even without Gloves of Midas? And by possible I mean better than 1 in 1000 shot.