Another thought.  Because of the condition code clobbering aspect of the 
new abi, you won't be able to mix code compiled with it with, say a shared 
library built for apcs-26 mode.  Maybe you realised this anyway, but it is 
another of the restrictions.

Libraries built in the new mode will work fine with existing apcs-32 code, 
however.

Another thing we need to consider when switching to ELF on arm32 is the 
basic alignment we return.  Newer processors with architecture v5 (eg 
XScale) have instructions that only work on double-word aligned memory.  
With the current gcc settings we can't assume that, so we need to consider 
bumping the alignment at some point -- the move to elf would be a good 
time to do that.

R.