I've discovered that one can print an HTML file to the default printer by first converting it to rtf. As it turns out, OSX has a utility for converting html to rtf. Thus, if you take the time to write a text-widget-to-html converter it becomes easy to print that via the command line.
exec textutil -cat rtf -stdout $pathToHtmlFile | lp
provides native integration with printing on Mac OS X as well.
"What is 'Mac-native' printing?" [1