Konstantinos is right with regards to the package naming, we discussed this with the zlib developers at the time.
It is easily solved with a packaging solution though, Provides: as he said. You will have the same problems with something libjpegturbo if it forces NEON, or libmatrix shipped with the GLES test utilities we've seen in our bug reports (btw that is a prime target for some NEON optimization, Konstantinos can you throw some code in there) or in fact any library that has NEON code which is not properly inserted/overridden at runtime based on NEON hwcaps (the concern here is i.MX515 TO2, Marvell and nVidia chips which have broken NEON or no NEON at all).
Shipping a libturboz.deb would not be a huge imposition. Given that Genesi provides system images and installers for Ubuntu we can install it by default (TO2 support for installation is going away with Natty). For Debian main, and other distributions which need to figure on supporting more platforms than ours, and for Ubuntu in the future if they ever get their act together on supporting real consumer products instead of just dev boards (looking at you too, Linaro!) then it will have to be a user installable option, but this might not be any more difficult than supplying a metapackage for the platform (like omap-extra) with some Recommends: line, which can only be resolved using an external repository (partner, or so) which is not enabled by default. As soon as someone enables that repo they will have the option at next update to "upgrade" their system to these new libraries.
Unfortunately doing it from a distribution point of view takes away all the easiest potential for performance optimization, but I think the benefit of having it "standardized" is worth it.
Speaking of standardization, we have had a LOT of customer complaints about xscreensaver-gl being installed by default on ARM platforms. In what world does the common ARM SoC ship with a full OpenGL implementation bolted on? Users are clicking some random 3D screensaver and complaining there is no acceleration - users do not understand the difference here between GL and GLES. As well as making new packages (libturboz in some other repo), it will have to be automated or automatically educating users to understand why they need this package and why, in fact in some cases, they may not actually need it.