the sort answer is yes it can work, but the key to making it work is lots of testing and tweaking. BITS config is obviously gonna be key with regards to the throttling/timing, so take a look at the BITS policy that's available.
BranchCache actually works really well with BITS if you're not in too much of a hurry - i.e if BITS is throttled so that one PC can get a head start at each site then it's pretty sweet. So you might for instance want to make a collection of 'Pioneers' - PCs which will get the DL first and can then act as Branch DP's via BranchCache.
Win7 BranchCache is not quite as efficient as Win8.x but it can still achieve big Bandwidth savings if you configure it right. You're aiming for 1 xDL per Package/App/Update per subnet and that is achievable with a bit of effort.
We're just in the process of writing up a Whitepaper for this very purpose, but it won't be available for a couple of weeks. Next week we'll be releasing our (free) Reporting stuff for BranchCache which is a great help with testing as it contains SCCM reports on which client got content from the DP as opposed to Peers - so keep checking the website.
Hope this helps a bit, but feel free to drop us a line and we'll help if we can.