I was at the Mobile Broadband Congress in London today. The keynote speaker was a policy-maker for the European Commission, who discussed a whole raft of issues like 900/1800MHz GSM refarming (good!), spectrum neutrality (controversial!).... and also mentioned (inevitably!) the new roaming caps.
Apart from voice roaming, he brought up the issue of data roaming charges, which have apparently been raised in a couple of letters to the Commission. At the moment, it's not intended to regulate them..... but....that's not necessarily going to be a perpetual state of affairs. He pointedly remarked that the new regulations task national regulators with "monitoring" both voice and data roaming, and that everything would be reassessed in 18 months' time. His comment to the effect that he didn't "believe that operators would make the same mistake twice" was tantamount to a pre-emptive shot across the bows, in my view.
He also raised the question of whether mobile broadband services could fit into the same regulatory framework as normal broadband - an open question, although it seems more likely to be defined as a separate market.