try this link...
http://www.leftybass.com/secondh...it's possible to make a regular upright for a lefty but consider a good amount of work...and since an upright's top doesn't have the same thickness on bass and treble sides...the fingerboard is also to be remade...there are two options : buy a regular upright and make it beig reversed by a luthier but it will never be as good as option 2 : ask for a custom made left hand upright and ...hope u have big bucks...
something else...there's a german manufacturer who makes lefty electric uprights ...not sure but try searching for fichter basses...alembic too...
good luck