From having done a bit of googling on this it seems that it is or at least was possible to do this with Sublime Text. I have seen multiple references to a preserve case button in the find and replace pane which looks like 2 rounded squares superimposed on each other.
However, I can't find this at all in my version of Sublime Text 3 (on Mavericks)...
Also I checked preferences to see if this option was somehow turned off but the only reference I could find to it was:
{ "keys": ["super+alt+a"], "command": "toggle_preserve_case", "context":
[
{ "key": "setting.is_widget", "operator": "equal", "operand": true }
]
},
in the default key map file...
Here is a screenshot of my find and replace pane:
