sorry to hear about your fall, i hope you feel better soon. best of luck.
yeah, i'm a little confused too. if you are talking about "reducing and downsizing" i don't really see how any 1 series body could be considered.
are you trying to reduce on price, size, complexity, etc.?
if i was trying to reduce or downgrade on price i'd probably just buy a mirrorless aps-c body. If so i'd look at the fuji(with the f2.8-4 kit lens), nex, or if you want Canon, the EOS-M. If you want something good enough and simple, you might look at one of the new fixed lens aps-c like the Ricoh GR or the Nikon Coolpix A.
If you just want one great and simple option why not the RX1 from Sony?
Otherwise i'd just keep the 5DIII and the 24-105, or even switch to a 24-70 f4(cant believe I just said that!)
the 5DIII is an awesome camera and you've had amazing lenses, I think you'll be disappointed if you try to go for the cheap zooms.
I'd say stick with what you have, buy primes, or switch to a much smaller system(think nex, eos-m, or even RX1.)