it is possible to end up in situations like this:
- dev-ruby/awesome_print-1.6.1::gentoo (masked by: use flag configuration mismatch)
when an old binpkg exists and no ebuild exists any longer. It is a very confusing error message that basically boils down to "the binpkg is bad and we can't rebuild it" which would be much better served with an option to not consider the binpkg if it's out of date and cannot be rebuilt (in my opinion).
One possible solution to this (which may be insane) would be to calculate deps based on ebuilds only, and then see if binpkgs happen to be available which match.
For the specific situation that you've encountered with the unsatisfied awesome_print dependency, I would expect the new output to be something like this:
- dev-ruby/awesome_print-1.6.1::gentoo (masked by: corresponding ebuild is not available)