The GNOME project at 15

I'm not convinced this is a big issue. So long as you have a simple build system which works, and clearly state dependencies, it should be easily packagable by any distro that the users care about your project on.

Targetting one popular distro's library versions and creating a package for that, with an easily buildable and repackagable source, gets you as far as you need. Nowadays distributions are far more standard and regular in things than you may think.

I get the impression from your post that you're really concerned about the difficulty in getting proprietary software packaged for many distributions. Ultimately that's a problem caused by their own restrictive licensing terms, and I don't think trying to enforce exactly the same versions of key software on all distributions is a sane way to fix it.