Multiple Vlans with DHCP

I have a project that I have jumped into that has got me in a dark corner thinking about ways to accomplish this, I am hoping I am missing something and there is a simple solution :)

My site is a big residential development that for reasons (which I can explain if necessary) needs a separate VLAN per apartment, and there are 680 apartments. So we are looking at around 700 Vlans each with its own gateway and DHCP pool. The Core network includes Brocade L3 switches and Sonicwall firewalls, and whatever else we need to make this work.

The issue here is that even the top-spec SonicWall firewall is limited to 512 VLANS - I have a similar project that was completed successfully and worked very well but it only had 300 VLANS, so the VLAN interfaces sat on the firewall and also gave out the DHCP, etc all from the firewall so was relatively simple.

Is there a way to achieve this? Would it be ok to put all the VLAN interfaces on the L3 switch then add a dhcp helper address to a dhcp server?

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Any suggestions welcome!