I believe you can mix F3 and M1 card in the same vDC. The M1 will do the routing and the F3 will do Layer 2 switching.
As per the latest release note for NX-OS 6.2 for nexus 7000, only M2 cards are interoperable with the F3.
With that being said, the document also states the below:
"With Cisco NX-OS Release 6.2(6), you can interoperate the F3 Series modules with other types of modules in the same VDC, in a lowest common denominator mode. The following combinations of modules are allowed:
In both cases, all modules perform full Layer 2 and Layer 3 forwarding based on their native capabilities (there is no proxy routing with F3 modules as on earlier M Series and F Series mixed VDCs). Therefore, only features that are common to all of the modules in the VDC are supported, and available hardware forwarding table sizes are generally equivalent to the smallest forwarding table sizes of any of the modules.
With Cisco NX-OS Release 6.2(6), you cannot interoperate the F3 Series plus the F2 and/or F2e Series plus the M2 Series modules in the same VDC."
Based on this information I would say having M1 and M3 cards is not possible. It clearly states that proxy mode is not supported with the F3 and M cards, making Leo's assumption on F3 & M1 same VDC configuration incorrect.
Also I think by making it not possible to have M2+F2/F2e+F3 in the same VDC, cisco is trying to encourage customers to adopt/migrate form second generation F cards to 3rd gen F cards.
Please refer the release note bellow: