hm that is good to know! Haven't used KDE for a while though but maybe it's time to take it for a spin again.
Ah it seems that there is this program called keynav. Something I guess I could have guessed.
For browsers I love to use these pentadactyl/vimium/... extensions. Would there be anything similar for reguar desktop applications. I get that it would be a huge effort to support all the different toolkits though.