Have you checked out PowerD, it's PPC native- I don't know if it has enough add-on modules for you, but it's very good otherwise.
There Mattahtias BASIC which is in Alpha state-
http://sourceforge.net/projects/mattathias/
http://www.liquido2.com/modules.php?op=modload&name=phpBB_14&file=index&action=viewforum&forum=6
The Blitz 68k exes will still run very fast on a Peg- I'm talking to the AmiBlitz author (who has inproved the compiler etc), and we may get the Editor working on MOS. But you still should be able to use the compiler and a text editor like GoldEd/MorphEd. I don't know about the debugger though.
And Pure Basic should work too- and that may be ported to MOS in future- the author says he'll see.
Another option is Python.
- Ants