Only for Sendy 1.1.7.8:
I've just modified report.php in order to allow to select the number of lines displayed (instead of 10).
Screenshot: http://dl.dropbox.com/u/406945/screenshot-sendy-1.1.7.8-report-hack.png
Download: http://dl.dropbox.com/u/406945/sendy-1.1.7.8-report-hack.zip
To install(Only for Sendy 1.1.7.8!!!): just replace report.php by the new one in your sendy installation
It's a very very small modification, but I've found it useful: I hope it can be useful also for others
Bonnes fêtes !