I just send a poc for lxc to the dev mailing list.ok, I'll wait for the next version.
We are using EfficientIP as IPam, so as soon as it will be available,
I'll surely take some time to make this IPam available for proxmox.
The ipam management itself is already done, with internal ipam but also external ipam like netbox,phpipam,... We just need to implement it for lxc/qemu.
BTW, if you have special needs for ipam, you can contact me directly to my email : firstname.lastname@example.org. (I'm French