Hi,
CRM 2013 release candidate is already available on partners for on-premise version. You can always use this for the development and when online one becomes available, deploy it there.
I would recommend upgrading the 2011 forms to 2013 on-premise first and have a look at the impact before going online. You can design your forms and processes that way too. We are using the same process for our customers already.
Hope this helps.
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Minal Dahiya
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