In the most recent (and arguably most forthright) installment of Iwata Asks, the Nintendo head honcho sat down to bounce a few questions off of a few members of the company's Development Engineering Department regarding the recently released Nintendo DSi. The devs outlined an interesting history of the shutterbugged handheld, one characterized on their end with "some frustration" -- apparently, sticking to the technological standard of an extremely popular device while simultaneously increasing its desirable features is a difficult compromise to make twice intwo years.
One of the interesting features that fell by the wayside during this compromise was an additional DS cart slot, allowing the handheld to house two titles simultaneously. This feature was apparently included in the DSi's initial design, but lent itself to a slightly bulkier frame for the handheld, much to the chagrin of Nintendo's Entertainment Analysis and Development division. They shot the design down, leading to the single-cart, slimmed-down design that's currently taking Japan by storm. Man, where were those guys when the Virtual Boy was designed?