Based on recs here, I finally found the Saigon Deli. It's on the northbound side of the 1300 block of SR7/US441 in Margate (NW Broward). Very chowish, clean and simple inside. The usual pho, bun and com dia menu, with a wider selection than the two pho joints on 441 south of Commercial, but less than a formal Vietnamese place would have.
Word is they have good banh mi, so that's what I got. Good, crusty baguette, impeccably fresh meat and vegetable fillings, toasty and warm on the outside and cool on the inside. No complaints here, and defineitly the best Vietnamese sandwich I've had in South Florida. It didn't come dressed, though. Right or wrong, I've always had them sprinkled with something like nuoc cham, that thin, fish-sauce and chili spiked sweet sauce normally served with spring rolls. I reckon next time I could ask for some. Plenty good enough, though.
I also tried their summer rolls, which were fresher than most; the skin wasn't rubbery from drying out. Over $2 seemed like a bit much to charge for salty lemonade, but they use bigger glasses than most places, so it was fine too. Thumbs up. Next time I'm around there, I'll try their real cooking.