I've got a few machines with mSATA adapters. All run great. My 1.5ghz 15" PB G4 is probably the closest to yours, and it's got a 128gb mSATA drive with adapter. Gave it new life.
My other machines with the same setup are:
-1.33ghz iBook G4 running Debian Bullseye/sid
-1.0ghz TiBook running Leopard
-1.25ghz 17" iMac G4 running Leopard (with a 3.5" to 2.5" adapter as well)
-400mhz (dosdude1 G4 upgrade) Bondi Blue iMac G3(4) running Tiger and OS 9.2.2 (ditto on the 3.5" to 2.5" adapter)
My 12" 1.5ghz PB G4 has an old OWC Mercury Legacy Pro SSD in it, but I'm going to change that out for the adapter solution soon, as it's always been a little slow; something I realized after upgrading my machines with mSATA drives and adapters. I'm going to take it apart and find out if it's just a simple mSATA adapter, and see if maybe I can upgrade the drive in it.
I also have a 1.42ghz (overclocked original) Mac Mini G4 and a 667mhz TiBook (VGA) with SD adapters; both 64gb and running OS 9.2.2.