I use a backpack daily to carry my EDC. It is very light but my EDC is pretty light too. Its got more than enough room to carry some extras I might need or things i may buy. Its not unlike all the backpack links you got earlier.

The nice thing about a small daypack, or climbing pack, style is that they do NOT look militaristic and blend in with the civilian world very easily. Go with a normal looking ruck and you won't get a second look.