I just started playing around with jQuery - and found it fascinating...
...however I saw some logical bug in the datepicker.
As one, who works on RTL web automatically tested datepicker like that.
The only problem I had is about the place of the button used to open the calendar.
jQuery states that if it is a LTR control the button should be after the original control, but if a RTL one the button should placed before.
In fact it is true ONLY if you have a LTR page with some RTL controls on it.
As I see this kind of LTR-RTL mixing is very rare (in fact never see something like this), in a real web the page itself set to RTL in wich case the rendering order of the controls swiched.
It means that in both case the button should be after the original control.

[the wrong one]

In jQuery source (of the datepicjer) there is a line like this:
input[isRTL ? 'before' : 'after' ]
The problem with it that you have no deal with the reordering of the controls, it's 
done by the browser rendering engine.
Changing the code to insert the button always after the control works perfect 
in RTL pages as well.

[the good one]

I write this long post to tell, that in RTL mode you need not reorder the controls 
not here (in datepicker) and not anywhere else. 
All modern browsers are rendering the controls as expected.

I think (but not checked) that this idea of reordering may appear everywhere in jQuery, 
and it is wrong!

Think about it...