In case anyone's interested, I've done an initial port of Steve Waring's
HTTP 1.1 client library
(http://www.dolphinharbor.org/dh/projects/httpclient/index.html) to
Squeak.

It's available from SqueakMap:
http://map1.squeakfoundation.org/sm/package/15f42ec1-e93e-4bcf-ab2b-6746ae9d413f

According to Steve, the features are:

    * HTTP 1.1 persistent connections.
    * Ability to process requests in a background process and set
timeouts.
    * Cookie parsing/sending.
    * Partial range requests.
    * Automatic following of redirections.
    * Streaming of responses to writeStreams/fileStreams.
    * Basic Authentication.
    * Support for Proxies.
    * Flexible progress notifications.