Personally I've recently switched from conventional AA rechargeable NiMH batteries to low self-discharge NiMH batteries (branded Eneloop) and am very impressed - things like my keyboard and mouse were needing to be recharged every 2 days or so and now I can go 2 weeks or more.
If you have enough light in the room a solar keyboard is also pretty awesome, I had one for the longest time. Kept it until I accidentally broke the keys cleaning it. Keyboard selection is very much based on taste though, so I assume you probably saw one and didn't like it.
And I can't help but notice that if you take this at face value and this really does multiply alkaline battery life by 8, the economics still roughly work out as a tie with existing NiMH batteries in terms of cost... and if the tech fails to do 8x, which I tend to agree is quite likely for the vast bulk of uses, it still leans in favor of NiMH for most things.
(Other brands do low self-discharge MiMH batteries too -- e.g. Duracell -- but I've had much less luck with those).