1) I downloaded relict binary qemu-0.9.0-i386.tar.gz, unpacked it and ran my disk image in this version. And magic! I got the speed I used to see.
2) I compiled kqemu for this version installed and tested it. I didn't see any difference in speed.
Size of binary qemu-0.9.0-i386.tar.gz is 3.8Mb and size of qemu-0.12.2-1pclos2010.i586.rpm is 18Mb. Best is the enemy of the good enough indeed.