ooh, this looks really problematic on multiple levels (why wait for JS etc).
A simple solution, which I've used--and I think the OPs situation is similar--is to just have an additional A-record pointed to the ELB, this should work unless the OP is doing something really fancy. No need for route-53, even go-daddy will let you do this.
However, route-53 gives you much better TTL, so if you ever need to re-route..
Interesting - from what I remember of the the original Amazon Dynamo paper it seems the ring replication is pretty central to the thing (if we are both talking about the ring replication used for the distribution of keys across the nodes).
This is sounding like crippleware :(
A bit tangential to this particular announcement - but i've been musing about using Riak, though so far put off by their (seemingly) open-core, rather than open-source implementation. Are the paid, enterprise functions stuff you eventually need in most use cases? the lack of multi-site replication in particular is curious; would this mean I can replicate between nodes on the cluster, as long as they are in the same datacenter, but not across the interwebs until i hand over some $$$?