Well the scenario here is not importing login Ids to the brand new server. If the destination server is a brand new server I can use the procedure you suggested, bcp out and bcp in of syslogins table. The destination server already has many login Ids and if we import (using bcp) syslogins form the source server, there will be conflict in the suid.
The destination server is an existing server and we are merging many databases from different servers to this one server.
Any way I found a solution (tested in dev but yet to implement in production):
1) I created login Ids (sp_addlogin) in to the destination server for the entire login Ids (except for sa & probe ids) from the source server with dummy password.
2) Then exported (bcp out) only login id and password (name, password) from syslogins
3) Imported (bcp in) above data into temp table
4) And finally updated the password column of syslosings