I agree that Dumbledore doesn't seem able to get Lucius to delay the trial. But I suggest that Harry could suggest an agreement to delay the (irreversible part of the) punishment.
Since the only fixed rule of the wizards' council is there are no fixed rules, such an agreement could be made. "She's guilty, and we'll house-elf her in a week." Since Lucius' priority is protecting Draco, genuine proof that someone else tried to killed Draco would be plenty of reason to release Hermione -- in exchange for Harry/Voldemort's help against the villain.
From Harry's point of view, especially, why should Lucius exact a high price to postpone the house-elfing of Hermione by a week or a month, as long as he has the formal verdict and the young villain is under secure observation somewhere?
EDIT: New discussion thread here.
This is a new thread to discuss Eliezer Yudkowsky's Harry Potter and the Methods of Rationality and anything related to it. With two chapters recently the previous thread has very quickly reached 500 comments. The latest chapter as of 17th March 2012 is Ch. 79.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author's Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: one, two, three, four, five, six, seven, eight, nine, ten.
As a reminder, it's often useful to start your comment by indicating which chapter you are commenting on.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: