After checking RFC3501, the UID
command (section 6.4.8) seems to be able to do part of this:
The UID command has two forms. In the first form, it takes as its
arguments a COPY, FETCH, or STORE command with arguments
appropriate for the associated command. However, the numbers in
the sequence set argument are unique identifiers instead of
message sequence numbers. Sequence set ranges are permitted, but
there is no guarantee that unique identifiers will be contiguous.
Thus, you should be able to call:
UID FETCH 412444:412500 (BODY.PEEK[TEXT/PLAIN OR TEXT/HTML OR TEXT/RICHTEXT])