Hello,
For those interested, I have made available a first draft of Bibi (a port of BYOB 3.1, based on Scratch) loading and working on Squeak 4.4 at this address:
http://www.zogotounga.net/comp/squeak/bibi.zip
It still has some rough edges and performance issues but is mostly usable; you should be able to load any Scratch or BYOB project and save them back, although in an upgraded and thus incompatible format.
Bugs are to be expected...
Stef