i've still not seen it in a working state but CxBx seems to be one of the most promising underground utilities/emulators for achieveing this.
and yes you could... but only in the way that you could use VisualC++ to program DarkBasic programs, creating an editor for the language that you'll really be using
GBA uses C/C++ with Assembly from what i can gather, so your best bet is to try a GBA developers forum and ask there what your next step could be.
Tsu'va Oni Ni Jyuuko Fiori Sei Tau!
One block follows the suit ... the whole suit of blocks is the path ... what have you found?