So here is the setup: I have two jquery datepickers, inside a jquery tab, inside a jquery modal dialog window:
\\---/\\---/\\---/_______________ /
Try putting the contents of the JQuery UI Dialog into an IFrame. That might help you get around some of your issues.
\---/\---/\---/_______________ / / \ ####IFRAME###### \ \ # # \ / #DATEPICKER1 # / \ # # \ / #DATEPICKER2 # / \ # # \ / ################ / \ \ /____________________________/