There is a reason why I build my 2p packs that way - I find that having 2p x s (where s is the number of cells in series) is better because there is less balancing required, and it provides an average voltage output for two cells instead of just one, which can help alleviate the effects of single weak cells. To balance 3s x 2 in parallel, there are 6 total cells which need to be balanced individually to be properly balanced, which is a wiring nightmare when it comes to balancing. Granted, A123 cells don't really need balancing, but it doesn't hurt to have the option.
I never did get any pictures of the process I use to build my A123 packs. But I can tell you that it does require a lot of time with a soldering iron (and a good one at that - the outer cans on A123 cells are aluminum and can absorb a lot of heat).
The vents on A123 cells are at the very center, I think on the positive side. But I never really was sure if it was on the positive or negative side because both have circular ports, so I just soldered everything the same way. Here's a picture of how I would make 2s2p:
That's copper braid strips, laid across 4 cells, where the cells on the left side of the dashed line are positive (or negative) and the cells on the right are both negative (or positive, as long as they are opposite of the left). Then I fold the copper braid at the dashed line to make a double-shotgun pack. The image on the right is a view of either end of the pack, where the cells are soldered together as shown.