I think it might be a convenient way of shifting, at least with a 105-key laptop keyboard, where both current shifts are kind of hard to press without straining some. Unfortunately I don't know of any layout implementation that'd support this natively, but I suppose the people here knows a little bit more than me on that matter.

To make the shift keys more accessible, use a Wide ergonomic mod. That way, your fingers will be one key closer on the right hand (and arguably a bit closer on the left hand on a 105-key/ISO board) to both Shift, Enter and Backspace.

Thanks for your feedback. Could I ask some of the fast typists around here to do a little test for me? I would like to measure how often you release the spacebar after the first letter of a word (to see if my idea will be viable). For me, that's almost never, but I'm still a pretty slow typist.

I've made a quick script to track typing events: http://nikitakit.ulmb.com/keyinput.html  If you have the time, could you try typing in it? The top area is for typing text, while the bottom echos all the events - I can look at this data to see any overlaps between key presses and releases.

EDIT: the old link was http://pastebin.com/p8eRNvpe but downloading is not as convenient

I don't see how that'd be any different from the current shift key. It's exactly the same thing, but with another key. Have you misunderstood something?

But that wasn't the problem in the post i quoted.

EDIT: Oh, sorry. It was. Just me reading sloppily.