Amex Credit Line Reallocation - Now Available (again)
Thought this might be of interest here.
I recently called in to reallocate my credit line from my old Blue Cash account (which I barely use) to my SPG card. Tried doing this in 12/2010 and 01/2011 to no avail, with agents claiming it would be available "soon". Apparently it is now available.
The agent also explicitly confirmed that this is not processed as a credit line increase request, and there is no pull on your credit or Amex-specific history.