Right now, CapsLock does one thing. You tap it, and toggle the state of the Caps Lock function. Why not make it do more than one thing, namely by giving it a different function when held down? Perhaps it can act something like AltGr. I personally a held-down CapsLock to generate small caps (via Unicode, so I can't demonstrate here) thanks to AutoHotkey.
I also have other overlapping assignments, such as the AppsKey (aka "Menu Key", which may or may not be what they're calling the "Right Mouse Button" in the article). Tap it and it does the usual. Hold it down and it generates lookalike characters if any exist for that key (otherwise it generates nothing, so you know you didn't get a lookalike), such as a Cyrillic a or capital letters from the Greek alphabet. Why? Because of wordfilters. I encountered one that liked to change all instances of "moot" to "cuck", but it did so with no regard to the characters around the string. Thus the word "smooth" became "scuckh". I dodge this by substituting Cyrillic o in place of one or both of the ones in the word. Another wordfilter I've encountered changes all instances of "wing" to "wang", including when it's part of the word "swing". Time to bust out the Byelorussian "i".
Another option is to map CapsLock to Ctrl (as many people do), or to Backspace (as is the norm in Colemak). I actually use it though, now that it has the additional Small Caps function. I tried the Backspace assignment, but found myself not using it, and now I have a duplicate Backspace to the left of the Left Shift.
Other funky double assignments: NumLock sends a Ctrl-Enter, but only in Skype, otherwise it behaves normally. My numeric keypad is also paired up differently and uses all five rows:
*, 4-Ins, 5-Home, 6-PgUp
-, 1-Del, 2-End, 3-PgDn
+, 0-Ins, Up Arrow,
Ctrl, Left Arrow, Down Arrow, Right Arrow