Originally Posted by SnaggleTooth
There are two answers to this question.
1. As far as official ones go, the cost of making them greatly outweighs demand.
Designing a controller is probably way more complex and expensive than you might think. I mean, microcircuitry alone is a massive pain in the ass to deal with in general for various reasons, but there's also all the small plastic bits, buttons, ports, rumble motors/accelerometers/etc, distances between buttons, weight, balance, testing and mass manufacture costs. In fact, it's actually kinda remarkable that one controller can suit such a large range of hand sizes as it is. Also, your complaint appears to be a fairly uncommon one, so there's lack of demand to factor in as well.
But there must be at least a small demand for such a product, right? So...
2. ...They probably do exist, somewhere.
Third party developed controllers, (madcatz, wildfire etc) at least back in the PSX/N64 days, tended to be gigantic and bulky by default. I'm willing to bet that they still are.
Also, I'd imagine that controllers that were specifically
designed to be larger exist anyway by some modding group/customising shop/gadget enthusiast/Chinese company on ebay. It's all reverse engineering and small batch/made-to-order type shit anyway. Probably worth a google if you're seriously interested in a comfy gamepad.