Superstars switch ultralite centre lock has the option of 12mm front however these don’t appear to be in stock. Some say that the superstar hubs are in fact in novatec hubs (rebadged) so you may be able to get novatec adapters to fit but it is worth e-mailing superstar.
Speaking of novatec the d771sb front hubs (which come in either cl or 6 bolt) have adapters to fit 12mm axles. Quite a few of the wheelbuilders like strada and bike clinic sell these hubs (although possibly not cl hubs) so it might be further e-mailing them. Bikestacja (polish website who quite a few folk here have used for wheel type products and also have an ebay site) definitely stock the cl variety but again it leaves you needing the adapters as they are only 15mm or qr.