It is not on the roadmap to enable for any existing hardware. The main reason is there are severe limitations to enabling dual-5Ghz operations on a dual-radio AP, and the overall performance is no where close to double the performance of a single 5Ghz radio (in many cases it's actually the same or worse than a single 5Ghz radio). Additionally, it requires very specific channel planning and limitations in what channels you can deploy (Cisco requires 100MHz spacing, which makes anything over HT40 impossible AND means deploying dual 5Ghz in large enterprise deployments is out). On top of that, in some vendor's implementations, like Cisco's Micro/Macro cell choice, so far we having see that being handled well by clients in regards to roam choices and separation, and it results in clients from anywhere under the AP picking whatever radio they start on and the clients end up salt and peppered around the AP instead of what we traditionally see.
That's not to say Aruba won't be making a dual-5Ghz, but we would be putting far more engineering into our solution than our competitors have to ensure that there is an actual, tangible difference in performance, rather than marketing hype. To see some real world tests, read http://community.arubanetworks.com/t5/Technology-Blog/Does-the-Dual-5GHz-Story-Stand/ba-p/271720