Yes, inlining is delicate.
For methods.. it would require non-virtual methods, which ooc doesn't have (except for covers).
For functions, once upon a time, using the ooc `inline` keyword *did* indeed generate C code with the C `inline` keyword, which *might* have in turn generated inlined code — but if I recall correctly, C compilers are under no obligation to do so, and it's one of the top ten things programmers do when they think it's going to make code faster, but it doesn't. C compilers inline themselves when they feel like it's going to be a performance increase, IIRC. (Of course, things get more complicated across modules...)
So, no trivial solution to your request, I'm afraid.
Cheers,
- A