I am not sure about those schools which you've listed but I know certain schools which do admit applicants with less then 2 yrs WE. But then, you would need to demonstrate exceptional strength in other areas of application. Obvious ones are Very strong GPA,GMAT and then lots of leadership/team stuff in extra-curricular/community activities. Even, if you've'd a WE of an year, make sure you've shown all such qualities in your work.
Lots of US top schools admit applicants who are college grads or have less than 2 yrs WE but that's a very very small % of the total admits. It is extremely tough but if you do your research and identify your 'fit' schools ( which also claim and have proved that they accept students with less WE), then y not go ahead?
P.S: I am an young applicant with 1 yr WE and 'm applying for Fall 2007.