Has anyone integrated Sugar with the MKTO Connector and Marketo Custom Objects? Can the Sugar Connector work with Marketo Custom objects?
No it does not.
And if you are using Sugar v6, you should avoid using the connector at all. The connector v3.1 that works with Sugar v7 does an honorable job, but still does not support custom objects.
Look into bedrockdata ETL Zak Pines