It appears that currently there's no way to use the "path-style" method for accessing S3 buckets (as contrasted here with the "virtual hosted-style" of bucket specification). Would it be possible to add an S3-special-remote configuration parameter to adjust the underlying S3 library's "s3RequestStyle" config parameter? I believe that the "PathStyle" value would be relevant to this specific request, as mentioned in the S3 library README.
The virtual-hosted style of bucket specification involves a lot of DNS overhead. In my particular use case, I'm looking at running Ceph with a radosgw with S3 support, and in fact the Ceph documention specifically indicates a preference for "path-style" bucket specification.