Nice! I run a similar service at https://ip6.name/. The service also supports empty groups, e.g. 2001.db8.8000.x.1.ip6.name resolves to 2001:db8:8000::1, as well as 2001.db8.8000.0.0.0.0.1.ip6.name.
A neat one is x.ip6.name, which resolves to ::, e.g. localhost...
A neat one is x.ip6.name, which resolves to ::, e.g. localhost...