As promised, here's what happened with my shipment:
rMB 1.3 512 silver, ordered 25th June Apple store France, estimated delivery was "3-4 weeks". Arrived on the 17th July (Paris) so, not particularly fast but also comfortably within the suggested window. Once the order moved from "processing" to "shipping", the estimated arrival day was the 17th July so they got that right.
Annoyingly, I got the "today's the day" sms from Apple on the 16th telling me to expect my delivery that day, so I stayed home for it... UPS then spent the day moving it from one depot to another in the outer suburbs (I watched the tracking site with bewilderment), and only at the very end of the day the tracking site said delivery would be delayed one business day. So it ended up arriving on the 17th as originally estimated after all. If I hadn't received the misleading text message from Apple I wouldn't have wasted a day waiting for it.
Anyway, it's here now and is as expected, quite lovely. Performance is fine, a bit of application switching lag at first but to be fair, I was running an update process on around 6 or 7 apps (and the OS itself) from the app store as well as pulling down apps I already have purchased previously (pixelmator, FCP X and a few others). Once that was done, everything became buttery smooth (within reason of course) and the battery life seems to be right on the money.
Currently trying to figure out what display res I like best for general use. Am switching between the built in "more space" option (1440x900 I think?), and 1680x1050 using Switch Res X. 1680x1050 is surprisingly usable for me and not really fatiguing, I even find 1920x1200 to be really OK to work with, except that it starts looking a bit less "retina crisp" by that point.
Really happy with it so far! The keyboard is hardly bothering me at all, from playing around with machines pre-purchase, I realised that the trick might be to remind yourself to just not type hard - even though the keyboard somehow makes you feel like you should. Once I got used to doing that, it's been great. Also I think a lot of people are getting tired hands because since the key travel is so shallow, you feel instinctively that you have to hold your fingers tense all the time (to avoid letting them rest on the keyboard) otherwise you feel like you might accidentally trigger presses. But that doesn't appear to be true. The keys may have little travel but they are firm and snappy, so you can just rest your hands on the keyboard as you normally would, even if you have big heavy hands like mine. Once you realise you don't need to keep your hands tense at all, you don't build up any undue fatigue, or at least I haven't.
Anyway digressions aside, my BTO order I guess falls into the 3 weeks from order to arrival timeframe. Would be curious to see if people who've made more recent orders are getting them any faster now.