The only thing that I was able to make is to have an NPC say something, and have that text box stay after interaction is complete.
Instead of msgbox I used preparemsg which will display text and without the release command won't hide it.
#dynamic 0x800000
#org @start
faceplayer
preparemsg @t1
end
'-----------
#org @t1
= Test.
After the NPC finishes talking, you can move around with the text box still active, but I'm not sure how to delay the closing time of the text box if you were to write more than one paragraph of text. I tried using the pause command but that stops player movement as well. The text box closes itself if you read a signpost or talk to an NPC. This information may not be particularly useful, but at least preparemsg doesn't require a button press to be stopped.