France Telecom has an installed base of 4.8m LiveBox gateways (mostly in France), and has >140k Unik subscriptions & has sold >200k phones (also mostly in France). Current run rate sounds like around 25k phones a month.
Have to say I'm surprised by the statistic that 15-20% of calls involve a handover - much higher than I'd have anticipated, although there's a possibility of self-selection here: I imagine the proposition is much more attractive to people who use their phones at home a lot. It could also be they've tuned the LiveBox WiFi to a smaller range and so there's some occasional accidental handovers to the macro network.
By contrast, BT Group plc (NYSE:BT) is reported to have (still) only around 40k Fusion users, although it's a bit opaque about whether that's accounts or phones. It has an installed base of "more than 1m" Home Hubs (I think it also said the same thing at end-2006, so I'd guess the number is a fair bit more by now).
Interestingly, although BT is being castigated for its slow growth, it looks like the penetration of dual-mode into homes with operator-provided gateways is broadly similar - around 3-4% (i.e. 140k against 4m LiveBox in markets where Unik has launched).
I've been saying for a while that UMA-based dualmode is only really an option when sold in conjunction with an operator's home gateway, in order to minimize costs of support and complexity of configuration, as well as enabling better QoS. It will be interesting to see if T-Mobile's promised full launch in the US will work around this and run over anyone's box/connection - as well as whether it incurs the wrath of Net Neutrality issues for running its mobile service "across someone else's broadband."
One other thing occurred to me - I think that the French aren't quite as voracious as the British in demanding the latest, most expensive, flashiest phones (ideally subsidized down to £zero). This could mean that Orange has had an easier time than BT in pushing the early unsexy, low-end UMA phones. Unik also has more attractive pricing, reflecting France's hugely competitive voice marketplace, and can offer free on-net calls to other Orange mobiles (incurring no net interconnect costs obviously), which BT cannot match in the UK.