I'm currently using namecheap, but I'd like to start adding ipv6 glue entries to my nameserver records, and they don't seem to support ipv6 glue reliably. What's a good, cheap registrar that supports ipv6 glue for the major TLDs (particularly .info, .net, .org, and .us)?
GoDaddy support .com and .net, not sure about the others.
gkg.net also support glue records apparently, although not used them.
There's a nice list for all others here.
Gandi.net has served me very well, and supports IPv6 glue.