I realize this is an old thread but the API's support it now
http://help.arcgis.com/en/webapi/javascript/arcgis/help/jssamples_start.htm#jssamples/map_wraparound...
http://help.arcgis.com/en/webapi/silverlight/2.2/help/index.html#//0166000000m2000000.htm
http://help.arcgis.com/en/webapps/flexviewer/help/index.html#/What_s_new_in_2_3/01m300000011000000/
-Sean