Hey guys,
After lots of problems with a certain video i've realised proxy editing and replacing all the clips in the timeline in vegas to 1080i clips is pointless as sitesl ike vimeo and youtube only support 720p. So, i'm converting all of the raw to 1260x720, min super converter (SUPER © . (http://www.erightsoft.com/SUPER.html)) i was wondering if anyone knows if the output can be interlaced, as i need to be slowing a few clips down and know its better when it is interlaced.
Thanks guys.

If you aim to work with 1280x720 clips, convert your 1080i to 720P60 to retain your slo-mo options.

I assume Super can do it ... but if not, Avisynth with a smart deinterlace plugin like TDeint works well.