An option would be to use the
ltxgrid package, developed by Arthur Ogawa as part of the
revtex distribution that is used to typeset papers for the American Physics Society (aps.org) journals.
ltxgrid package was commissioned by the American Physical Society
and is distributed under the terms of the
LaTeX Project Public License,
the same license under which all the portions of LaTeX itself is distributed.
See lppl for the license details.
As concerning the "moral obligation" of commercial use of
multicol I think the arguments you put forward, are contradictory and your concerns unfounded. You say in the comments:
...the just fee would probably be substantial and (b) there is nothing
wrong, and I indeed feel indebted to the TeX community; however, I am
barely in black recently...
The moral obligation is to thank the author of the package in any way you can afford, when the commercial venture is on the way and to make a contribution later on as you may deem fit once it starts generating substantial income and as you say the just fee becomes substantial. Same is morally true for any of the free source software, either being TeX related or otherwise. Just don't talk to a lawyer listen to your inner self. As I mentioned in https://tex.stackexchange.com/a/37352/963, the LaTeX project can do with some funding.
Many corporate beneficiaries of both publicly funded research as well as open source software have indigestion when it comes to giving something back to the community. You can find an interesting discussion at the HN thread Research Bought, Then Paid For: Open Access to Science Under Attack. I find this disheartening and a poor trait of the human nature.