[iso1631]

Public IP6s are allocated the same as ipv4, either ask for a block (I assume you'll need your own AS and appropiate method to announce), or your ISP hands you a block (should be a /48 I think, or maybe a /56)

Private you can do whatever you want in the fd00:: range

fd00:1:/64 for vlan 1 fd00:2:/64 for vlan 2

etc

Or

fd00:ea7:cace::/64

fd00:b00b:13s::/64

Or have your hosts on

fd00:192:168:0::1 fd00:192:168:0::2 fd00:192:168:0::3

(you don't have to have your router on :0 if you don't want to, just like you don't have to use .1 or .254 in a ipv4 /24)

If you want to allocate a given IP to a given mac address centrally then you need DHCPv6 as normal. The problem is that because dhcp isn't as required as it is under v4 (because of slacc), not all clients will support it, or support it properly. For desktops + servers you should be fine though.