Late, I know. Something like that would require your remote receiver to accept those codes by IR - for example, if you wanted CTRL+ALT+SHIFT+5, that would be a single unique IR code, not a combination or sequence of other codes. And yes, when you work out all the combinations, that means there would be a ton of individual codes.

If you had an RC6-compatible receiver, then Microsoft does accept full keyboard commands with modifiers (I have one of the original MCR IR keyboards with mouse pointer, media keys, etc., and it works just like a normal keyboard except it can be taught to any remote.)