Our view hasn't really changed. In general, for the vast majority of people, post-production billing is perfectly adequate. It's only if you are intending to run a hotel or a pre-pay/card billing solution that you would need an on-line/near-time solution. Here in the UK there are lots of organizations (some small some not so small) who can take your CDR data and produce billing for you.
Right now, unless/until someone funds it, we won't be rushing to do anything with integrated billing. For most small operations it's easier to just download the CDRs' into Excel and then you can do whatever you wish with them in terms of pricing and agregation.
Best
S