I would dump to tape, then have a service bureau dupe the betacam tape from that. Be sure to add 30 seconds or more of color bars to the head of your tape.
This may be a bit late...but you have a few options. You can go rent a beta deck w/audio converter to layy off to the beta deck. You could also create an avi file (or uncomp QT) and run down to your local post house and see if they can take your file and lay it off to Beta for you. Not sure I would dump it to DV and then have that bumped to Beta...you can do that, but your at the mercy of the dub operator and it may not be the quality and color you anticipated.
1) you could take your DV tape to a dub house and have it copied to beta
2) you could find a house that transfers to beta from their NLE and deliver them your project on a hard drive . if they use Avid you would go to avid site and download their codec ( i believe meridian codec) . you then render out your project using Meridian codec to whatever the houses spec's are ? ( ask them) ... if they have a decklink card ( either PC or mac) you would go to decklinks site and download black magic's codec and "render as" using the BM codec to the spec's that they tell you ( some use 8bit others 10bit)
YOU do not deliver a uncompressed QT or AVI " render As" using NONE = they would then have to render it using their codec ( for their card) = you pay for rendering time = big $$$$$ ...
the least $$ would be to have your dv tape copied to beta at a dub house ..
If you've got the money render to Sony YUV with a TINY amount of chroma blur to smooth out the DV jaggies or render using the BMD codec, most places should be able to dump such a file out for you from a HDD or get a DMB card with component output and rent suitable deck if it's Beta or Beta SP, if digi betacam then you only need the cheaper Declink card and a DVW 500 deck (definately something to rent, not buy!).
You do need fast disk arrays to keep up though. Thing is if you've got one job like this chances are you'll get more so the cost might be justified.
And congratulations on making it to the big time.
Bob.
If you already have a clean DV master in hand I'd find a post house or other facility that can do the transfer to whatever flavor of beta the master needs to be in (probably SP or Digibeta). If the transfer house can do the DV>Beta transfer over SDI, that'd be the cleanest but component should be fine also.