To me, with the setups that you've proposed, the decision I made would be based on the sound. Do you like the V3 or the 7xx with your MBHO's (there are plenty of samples out there of both)? If you're basing your decision more on form factor, quality and convenience, then I'd say to go straight to the 702 since you're say you'd eventually be heading in that direction anyway.
Lots of people prefer the V3 sound over the 7xx and run the V3 upstream of the 7xx. In my case, having the 702 behind the V3 was too much investment in the recorder end to justify, although I'd be the first to admit that the 7xx are second to none in quality and features. It's not that I wouldn't LOVE to have kept my 702, it's just that I couldn't justify what I had wrapped up in it for what I was using it for and opted to use a R-09HR and saved $1300.