Few proficient Perl programmers would choose your method, which is why you're not finding code already written to do this.

As others have said, Perl's editing features are powerful. It seems like the reason you're looking to use vim is that your proficiency with vim is greater than with Perl. If so, the correct approach is to improve your proficiency with Perl and edit your data using Perl instead of kludging something with vim.

If the data can be represented in a config format, there are many modules available to be used; just do a CPAN search on 'config'.

Even if your data isn't nicely represented in a config format, it's possible that CPAN may contain a module which will solve your problem without using an external editor.