Ok, D is not there yet, but I managed to build a crippled gcc-4.8 (with D) targeting arm-apple-darwin and I can compile simple C functions to .o files and link them into an iphone app. And run it on my iphone. The D and C++ compilers built, but I have probably a potpourri of issues since I gave 4.8 a arm-darwin target by selectively copying apple's 4.2 changes for arm-darwin. gcc-4.8 was configured to use tools (as, ld) in the apple iphone SDK.
The biggest hassle is that apple's version of arm as is different than binutils as. So I am learning what it wants for debug and pseudo op differences. Even a simple D module with just a extern(C) function depends on something in druntime, so I have to get part of that to build first. -- dano