One of the essential things identified is porting back the changes on the AmigaOS 4 version to the AmigaOS 3 version.
Not sure what is really meant here, porting back OS4-features to OS3.x ? Or just making making sure that new features added to say a OS4-version of ArtDeptPro are also made available in a OS3.x-version of ArtDeptPro.
DPaint is obviously very popular but has (moste likley) a few stopgaps :
- closly tied to the OCS/AGA chipsets
- parts written in assembler or worse languages
- owned by a company which wouldn't even react to such questions
What might be a good canditate is the MorphOS version of Papyrus, AFAIK only some minor legal problems and a runaway coder that lead to this to be mouthballed so dramatic.
Sources should be gcc-clean and the required level of MUI available to all systems (including 68k and maybe even AROS).