Gentoo armv4tl-softfloat-linux-gnueabi optimalized for Openmoko (-Os -march=armv4t -mtune=arm920t) on 2008.0/arm profile (glibc based, sane bootstrapable toolchain)
(embedded uclibc/arm profile armv4tl-softfloat-linux-uclibcgnueabi in plans)
http://www.gentoo.org/doc/en/handbook/handbook-arm.xml (Skip points 2 and 3)
As i'll be adding some packages to ftp above you might want to ask for some package here: GentooPackageWishList
Overlay with moko things and more packages coming soon.