Since it turns out that CentOS 7 is of questionable usability on ARMv7 without NEON such as Tegra and Tegra 2 (Toshiba AC100, TrimSlice), it looks like I'm going to be actively working on some RS things again. One of the things that has been a bit of a stumbling block for me recently is the limited usability on machines with only ~500MB of RAM. I am thus going to embark on a project to rebuild as many packages as possible with -Os instead of -O2, along with a few other tweaks. I intend to call this project ShortSleeve (because it's mainly useful when your RAM is too short).
The way I envisage this to work is via a separate repository. All the packages will have their Epoch bumped to 1 so that you will be able to add a .repo file and do yum update to get you all the available ShortSleeve packages in preference to the vanilla ones.
I am hoping to kick off the building this weekend, and packages will land on the server as and when they build. Before you feel tempted to dive straight in, you should be aware that this will be poorly tested, highly experimental, and very incomplete for quite a while. Do take it for a spin on test machines you don't mind having to restore from backup and report any differences in memory usage and performance. DON'T assume it will just work and run it on anything important.