i do but i cheat
when i tried to learn the guitar years ago, i learned right handed, and if i were to pick it up today and strum the few things i know, i'll still play it right-handed.
when i started to learn the to play the uke almost three years ago, i taught myself left-handed. i can't play the uke right-handed, however, i do play a right-handed uke (meaning i don't restring it for lefty style). i taught myself to play a right-handed uke simply because i didn't want to be extremely limited to not playing other's ukes or testing 'em out at a music store (sad thing is though, i've only played the two ukes i own).
this is one of the reasons i don't chime in on threads about how to hold an e chord on the uke (which i find super easy to hold). there is a lot of threads and what not where my advice to others would be is obsolete. plus i'm still not a great uke player, i am decent though.
as far as the strumming goes, i strum the way that adrine says, if he says down, i strum down, up, i strum up. as long as the ear can distinguish between the ups and downs, i don't think it's entirely noticeable that the sound of my strumming is backwards.