Yes, I believe I could get a "loose-leaf" visa, though I think those are supposed to be for a more urgent situation. I think they are the same cost as a standard passport visa, so no real gain there.

Just wondering about the anticipated VOA wait time for a Sunday evening (745 PM) arrival at SGN. Hopefully someone that travels through there a bit can shed some light on how busy it should be, any banks of international arrivals, and so on.