thank you for directing me to this discussion. ( i am almost the official person in Israel to talk to about these issues. in a few days i will know )
i keep an updated Moodle 2 HEAD copy over here and i am attaching the current state of the visual layout i get when i start to edit a new Quiz.
it looks very good. ( a little bit different than the capture screens you posted )
only thing is the new question dialog that has the DIVs swapped. if i change the style="direction:ltr;" i see the untranslated English text of the names of the types of the questions, correctly.
but i guess you can leave it. i will fix it when i get to it while i adjust the rtl.css file in the theme.
i am currently translating other parts of the system and as i get to the Quiz module, i will update you too so you could see some more (probably, unreadable Hebrew) rtl "strings".
btw, i was inspired to playing with YUI (on other parts of Moodle) as soon as i saw your "add new question" YUI dialog ! a while ago. ( i will keep you posted as i promised )