Yes, exactly like File -> Save Cue Sheet As! You are amazing, you implemented the enhancement already! In my defence, I looked for instructions on saving a cue sheet in Help -> XLD Help, and in http://tmkk.undo.jp/xld/index_e.html, and in the CDDB and Profile menus, but did not see any mention of this feature.
As an example, I set XLD to work on my difficult CD. After about 15 minutes, the progress displays as "96.6 %, 0.0x realtime, 10699:25 remaining". I could wait 7.4 days for XLD to finish, or I could press "Cancel", and lose the chance for a CUE file.
Looking at the code for r437, I have some idea where the relevant parts of the code might be. This is only from a quick read, so I might be mistaken. The CUE file appears to be generated by routine (NSMutableData *)cueDataForTracks:(NSArray *)tracks withFileName:(NSString *)filename appendBOM:(BOOL)appendBOM samplerate:(int)samplerate in xld-code-437-trunk/XLD/XLDCustomClasses.m:285-380 . The caller for cueDataForTracks appears to be routine (void)convert in xld-code-437-trunk/XLD/XLDConverterTask.m:787-1133...
Generate a CUE file without full Extract
Store MusicBrainz IDs in FLAC files
Clarify wording about metadata in UI
"Error: cannot write the output file" when Artist string is very long