And now I can say that I am definitely sticking with Puppy Linux Quiky on the Raspberry Pi 2/3.
While it took some work I managed to get OpenScad and RepSnapper installed (no luck with slic3r, though RepSnapper does the job). So I can do everything I need on Puppy Linux. And with everything I use installed, including DevX (the package that has all the GNU compiler toolchain along with just about every developer version library, and a few other programming languages) the entire system is taking about 700MB (plus the on disk structure of the Ext4FS [aprox another 500MB on this 32GB SD Card]). On Raspbian that would have taken about 4.5GB for the same set of software, even if I started with the minimal Raspbian and added everything I use, hence the power of Puppy Linux.
And the Rendering in
both OpenSCAD and RepSnapper
is a lot better in Puppy
Linux Quirky than Raspbian
And Puppy Linux is light weight enough to do what I have long wanted to do. Create a set of libraries that implement the source level API of RISC OS ontop of Linux, setup up the desktop Environment to be as close to RISC OS as possible, and implement a very quick (arm to arm) CPU Only emulation layer to run many RISC OS applications, as well as a BASIC V compatible BASIC interpreter including the assembler.
In other words have the best of both worlds (RISC OS and Linux), in a single OS. I had not pursued this as there had not been an appropriate base Linux to work from before now (at least not on the ARM).