Python is essentially uncrosscompilable and its maintainers have repeatedly rudely rejected efforts to make it so.
If that weren't the case, and the way installed Python modules were "managed" (I use the term liberally) were made sane, I'd think it were a fine thing to use in base. But it is the case, and that won't be made sane, and so I think it belongs nowhere near NetBSD. Could you translate your prototype into a different language, one that's less basically hostile to our build system and its goals and benefits?