As I understand it, using the build service to create a version of MeeGo without the SSSE3 requirement should be reasonably straightforward. In fact, I believe a few Moblin Meego developers have encouraged those who inquired about the possibility to go ahead and try it.

MeeGo system developers simply warn that compiling for older, non-SSSE3 hardware will create an operating system that is unbearably slow on netbooks. Also, as the core MeeGo developers are quite firm on the SSSE3 requirement, I'm not certain how interested they are in receiving patches for, say, x87 fixes and tweaks.