About the only place making barrels for CZs is Bar-Sto. You'll have to contact them. I think the SP-01 barrel is pretty much standard CZ-75B.
Bar-Sto does their CZ barrels once a year, however, and just finished their production run a month or so ago... so if you REALLY want a barrel, you may have to wait a while or see if you can get a Bar-Sto from a forum member.
(I think there was one offered not long ago, here, with a 75B, but it may have been a .40.)