The CRU (Comprehensive Review of USMLE) which is a committee formed by members from FSMB, NBME, and ECFMG is continualy reviewing the structure of the USMLE and how to make it better.
The issue of merging Step 1 with Step 2 has been raised recently (rumors are true) but it has not been approved by the committee.
The current exam structure of Step 1, Step 2 CK, Step 2 CS, and Step 3 will continue for the time being.
Here I quote for you the paragraph from their latest update:
"The overall structure of USMLE will remain stable at present, continuing to comprise Steps 1, 2 CK, 2 CS, and 3. In the longer term, it is likely that this structure will evolve to reflect other anticipated changes in exam content, competencies assessed, and testing formats used. Anticipated changes will be guided by CRU recommendations, and will consider (and accommodate to the extent possible) the diverse needs of the USMLE program's various stakeholders."
So they left the door open for future changes! but as of now there are no changes.
The full report is available on the net here
http://www.usmle.org/General_Information/CRU/Post-AAMC-USMLE-update.pdf