Paul White NZ,
I appreciate everyone's help. I simply haven't found a solution that fits my awkward/dumb problem.
I'll thank everyone when/if I have a solution, giving credit to the lucky solution that actually solves my problem.
I hope I didn't offend you by pointing out your XML config file is isomorphic to any bcp format file. The big differences are (1) bcp format file version number in plaintext version (2) plaintext version requires row count, whereas XML matches record description to column data description. Given a PEG description of the grammar, we can recursively backtrack through all the columns listed in the DSL example file, counting the number of columns, and shove that in the plaintext bcp format file's description.
I think you'll find that if you represent the problem using a Parsing expression grammar (PEG) then you'll get the best solution for what you appeared to be talking about: DSL definition (which seemed a bit off-topic to me). A pointer to a unique solution strategy is the best way I can say thanks for your time; most DBAs have never heard of a PEG. I am giving you input on how I would solve a problem elegantly, iff I had no weird constraints beyond my control (like the ones I described in this thread). (Technically speaking, you could probably use a Generalized Left-Right Scannerless parsing tool like the Oslo toolchain to do the same work as a PEG. DBAs might be more familiar with that since that toolchain is now being folded into SQLServer as "SQLServer Modeling Platform".)