Infor CRM (formerly Saleslogix) released an X3 integration last year. It was a high priority for them and Sage. The work on that helped pave the way for Sage CRM integration, if I understand the story right. The fundamental bottleneck was X3's unfinished sData implementation. Both Infor CRM and Sage CRM have fully finished sData, but none of the Sage ERP's had finished; X3 is, I think, the first to do so.
The key to cloud-to-ground CRM-ERP integration is sData. So Sage CRM Cloud integration to on-prem Sage 100 is waiting on Irvine to finish what it committed to do years ago.