@tdaviesCH6X9 Thank you!!! (& @emmi.viitala - just saw your post now)
I'm not sure if this was your intent, but I found this site by searching for "arial strikethrough" (use the "Long strikethrough" option) : Unicode Strikethrough - S̵t̵r̵i̵k̵e̵t̵h̵r̵o̵u̵g̵h̵ ̵T̵e̵x̵t̵ (yaytext.com)
I think it creates the "strikethrough text" using unicode character overlays, so it can be used WITHIN a larger section of text (i.e. you don't have to change the font for the whole element). The output is a little sloppy with multiple lines (line-wrapping gets messed up - especially if there's hyphens, and there are leading strikeout/spaces sometimes), but definitely worth checking out the next time I need it!
One other issue that I see (that might be a non-issue most of the time): there's no way to "take out" the strikethrough (correct me if I'm wrong) - you'd have to re-type the text (or copy from a previous version). That said, we shouldn't need that functionality most of the time.
BTW, we ARE using Revit for our General Notes now (using manual line-breaks for the roman-numeral workaround), so this is more relevant for us now. I can't believe how many years it's been...