Public/testing 4to6 gateway?

[Rick Ernst <nanog () shreddedmail com>]

Either they don't exist, or my Google-fu is particularly bad this morning.

I'm trying to get my toes wet with IPv6.  I've established an internal
6to4/4to6 tunnel.  I'd also like to have a testbed for access to public v6
sites.  I'm also trying to find some clue at my upstreams, but figured I'd
ask here as well.  Are there any 4to6 gateway available?  I have assigned v6
space.

Thanks,