Just do it already. The 6bone was built by IPIP tunnels exchanging BGP routes and much of the existing IPv6 Internet still consists of tunnels. Not very complicated at all. Here I'll start with this:
My tunnel endpoint: 67.53.202.230 My networks: 44.14.0.0/24 My ASN: 53810
BGP link/peering addresses negotiated as needed.
Peers are expected to adjust incoming and outgoing prefix filters to satisfy upstream and AMPRNet policies.
Contact me off-list if you want to setup BGP tunnel.