I'm sure something like this would be appreciated.
You can say that again!!
Imagining and open source survey/civil package for vanilla . . .
That is exactly what I would like to see!
It sound good, I have seen this before many times, it is possible, but requires a lot of effort.
The little I know on C++/ARX took me about three years to get somehow familiar, and another 8 months to developed my first full application with this language.
I found very little help from the masters, with the exceptions of CG, CB, FM, OW and BB and I maybe another two that at this moment I forgeting.... as you can see very few really are willing to lend a hand, and in the other side, it is not easy to code in C++ and worst in ARX.
Hope you find a team and come up with a decent product.
Good luck!