Additional brackets

I'd like a) curved brackets and b) closing brackets for situations where large symbols don't do the job. Example: I have several blocks of alternate fingering that I'd like to enclose in large paren-shaped brackets. Another example: an alternate phrase or section, set off with horizontal frames, that should be surrounded by parens or brackets. I don't see a convenient way to create these symbols. I can add large staff text, but typographically these look strange when blown up to 36 or 48 points or whatever is needed to enclose the material. Similarly, the curly brackets used on staves would be useful for annotation purposes. Both opening (right-facing) and closing (left-facing) forms would be helpful.