I use ultraedit for a lot of non mirc coding, and even that doesn't support such a thing...
Anyway, i would like to make a semi unrelated suggestion... maybe your code would be significantly smaller (and maybe prevent the need for such a feature) if you made good use of aliases setup as functions, rather than endlessly repeating portions of code.
Personally if i use a multi line snippet of code more than twice, i make a point of creating an alias to be called instead. (such as endlessly checking if the channel an event occured in matches a list, or if a variable is valid, etc)
