To what pixel dimensions do DV clips captured, then exported out of Vegas need to be converted for print purposes?
It seems that Vegas has an unusual output size. (655x480)
Pixels is a video/computer term that has nothing to do with the dpi of the printed image.
If you want to (BTW, I don't recommend doing this!!), you could print a frame grab as a 24" x 36" poster. The qualit ywould be horrendous though.
I'd personally go no larger than a 4" x 6" print.
Obviously, the better the quality of the original video image, the better the quality of the resulting print.
I've done that before (print publications) and never worried about compensating for different Pixel Aspect Ratios.
Do a frame grab, clean up in Photoshop as desired and print it.
655x480 is the frame size at a 1.0 pixel aspect ratio, which is what you want for most still image applications. Use that. It's correct. It's not unusual at all; it's just the size that NTSC DV images really are.