I've played with Sabotage Linux a little because it uses a libc (musl libc,
http://www.etalabs.net/musl/) that matches what I want:
-Standard ABI (fairly constant except for major bugs, aims at LSB ABI compatability so eventually it will work with glibc binaries)
-Small source, quick to build (maybe two-minute build time on an atom at -j1; uses hand-edited config.mak instead of ./configure shell script; 7.2 MB for the latest version of the source + 700 KB includes )
-Standards-conformant source interface (mostly conforms to X/Open. ISO C99, POSIX; treats nonconformance as a bug that must be fixed instead of "wontfix")
-Fully supports static compilation; designed so every function gets its own file for minimum link overhead, no extra shared libs that get dragged in behind your back,
-Small binaries (1.5 mb libc.a includes everything, when glibc takes 3 mb just for libc.a and then has all the other stuff; 550 kb libc.so vs 1.3 mb; and a static or shared binary will be smaller than when linked with glibc)
-Designed for low RAM use--the author wrote it because his computer couldn't run libc6 and libc5 was inadequate.
The standards-conformance attitude is an advantage over every other libc, ABI beats uclibc/klibc, size beats glibc.
I've pondered making a Puppy based on it, but don't know that much; but it sure would be nice for that purpose...
I'm currently working (slowly) on "Muslin", a musl-based Linux distro. The long-term aim is to have something light, fast, and X/Open (SUSv4/UNIX2008) conformant.