I was doing dual deck tarot readings at the local yule fair last week and what stood out to me was how people would create their own spreads, which didn't necessarily look like anything I'd create, but nonetheless made perfect sense for those people. What I liked about that realization is that it proves that fixed spreads are not a necessary part of Tarot reading. In fact, I'd argue that the spontaneous creation of new spreads made the reading more effective because the layout of the cards demonstrated the mental "space" of the person, and how the different cards were situated in that space.
Space, mental and physical, is part of how a person defines his/her identity. The manipulation of space via placement of objects is part of that identification process and it can tell a lot about what obstacles a person is encountered. A spread that is chaotic with elements all over the place still has an order to it, even if its an order that only the person who created the spread understands. A reading I recently did initially looked very chaotic. It took asking some questions to really get to the central issue, but once those questions were asked the spread made complete sense and fit the issue rather well.
What makes this approach dynamic however is that if you use a tarot reading as an act of enchantment, you can make the person's ability to change the spread, to reorganize it an essential part of the reading. In other words, the person changes the spatial identity s/he inhabits by changing how the cards are spatially organized, as well as how s/he understands the underlying message of the card. The result is a different reading, one that plots how the person will make changes to the existing pattern in order to resolve whatever issues are represented.
Here's a podcast episode where I talk about some of my initial experiments with Tarot.