Out of current appliances I would say that 1035 (or 1065) would be good replacement for 1030s:
Sales team can give you more details on these appliances so I would recommend contacting your local McAfee NGFW sales rep.
Lastly I want to mention one thing. Your old appliance FW-1030 runs 32-bit version of NGFW software while the new modular 1035 and 1065 appliances both run 64-bit version. State synchronization between the two architectures is not compatible and thus it's not possible to run cluster with one 32-bit (1030) and one 64-bit (1035) appliance online at the same time. So this means that when you replace the old appliances with new ones, there is going to be short outage when you replace the second old appliance with new one.