Your original Idea, Matt3o, concerning the text-mods is very reasonsable. Going for consistancy in lines and font-size... however I understand that the comunity wants their words
.
But... (of course there is one)... given that you do not, and with this font can not, write out "insert" and "delete" anyways in the 6 keys block, it shouldn't upset people to much having the "pgup" and "pgdn" (which because you use capitals all the way would also look good) in the same block (it's a reasonable argument too)... that way I think you should be able to go with the big font size there and have a very nice 6 keys block.
For the "scroll lock", "print screen" and "pause break" as it is you don't have an option (because "scroll" and "screen" are killers), so I would stick with the smaller size for these three keys... then see how it looks in the layout.
Also if you stick with the smaller size I would feel (sry for bringing another problem) like you would have to go with that "rule" for "num lock" as well.
One more small thing that maybe helps optimize the dual lines for "print screen" etc:
Notice how subjectively the vertical space between "print" and "screen" (because of the smaller font size) looks relatively bigger than say the one between "caps" and "lock". You could try to reduce that space by just a very small (almost not noticable bit) in order to make the two lines stick together just a little bit more.
Spacing between letters, yes, I see why you don't like it and it's difficult to judge too. With those wide Capitals however it is possible to a degree. In this font for example "down" is a real killer because of the "w"-spacing. Usually the spacing is mostly done with bigger headline-fonts and the font you chose comes well spaced and doesn't really need it. But it turnes out also not to be the solution here, I think, because it still offers too little possibilities.
As for the Logo, it's good that you have a test-run... that way you can take the risk, I guess.