I can't answer even half the questions I'm being asked in my email inbox. Sorry. So I'm moving the conversation here.
The only thing I know is that Xam hope to demo something about PCLs sometime around the time of Evolve - so we're really close now to having amazing Cross-Platform support :)
Until then, the safest route is probably to use the old Mono tools, VSMonoTouch and the patched version of 3.1.1 - http://slodge.blogspot.co.uk/2013/02/a-patched-monodevelop-for-pcls.html - that's what I'm using right now today.
Alternatively, if you find something that works, please post it here :)
And if you have questions then again ask them here - hopefully someone here will be able to help you out.
We will get there - the future is definitely portable :)
Thanks (sorry I can't help more!)