I thought it was possible to do all of this without using visual studio - or any other IDE - with the possible exception of the WinRT app submission process.
I know you're wrong about sqlite and linq as I've used them on both .net and mono. I think you're using the phrase "portable library" incorrectly. In the .net world, these are libraries created by microsoft that use the more limited version of the framework on their other platforms. For example, windows phone 7 and win rt use different portable libraries (a pain to manage, admittedly).
It is easy to be confused, because PCL is confusing.
My personal preference is to just link source files and use partial classes (very much like the Linux kernel uses "pluggable" files to create a kernel) to create a product.
The problem is that there is no "Portable Class Library", there are dozens of profiles, and you need to pick the subset you want, for example: "Desktop and Windows8" is a much larger profile than "XBox and Silverlight", the subsets are different.
If you ignore Xbox and Silverlight, you pretty much have the whole stack everywhere.
I know you're wrong about sqlite and linq as I've used them on both .net and mono. I think you're using the phrase "portable library" incorrectly. In the .net world, these are libraries created by microsoft that use the more limited version of the framework on their other platforms. For example, windows phone 7 and win rt use different portable libraries (a pain to manage, admittedly).