Hi,
Still think you should try another dealer. Close to Brussels is a dealer (Hope this is not the one, else I'll have a word......PM me if needed, @Kortenberg approx. 20 minutes from centre of Brussels) I am sure they would be willing to help you. (might need to have an appointment, maybe even get a demo at home)
Back to the ranking….
I do have about 40sqm as well, the BL6000 with subwoofer (BL11) might just be enough. (although I did not like them with BL2, bass was all over the place) They sound great on their own in a smaller room though(12-16 sqm).
BL4000 only, great bass and that in such a small package, better than the 6000's without sub, but never tried them in a room that size.
BL4 + BL11... must admit I have only heard these in a shop not to keen on having them in my living room, with or without sub.
BL3, can't help you with that, although I am quite impressed with the acoustic lens in my current BL9s and other people's reviews, they are on my wish list to accompany my bv10 in the bedroom.
Anyway, if you look at the responses you probably realise it is very difficult to say what the best option is, it is also a bit of a personal opinion ( I might get bitten with this statement...), some people love the BL4000, others are impressed with the BL3. The BL6000 lacks some bass which should be complemented by the BL11, however if you speak to the missus she prefers the 6000's as they are not so 'in your face' (I am allowed to quote her
)
And ( I know it sounds like a broken record), to come back to the other replies, if the dealer cannot provide you with the setup you prefer to listen to (I mean whatever is technically possible) you should walk away and look somewhere else, it is too expensive to get it wrong. Once you have listened to them in the shop and made your choice, try and get them installed in your own house, any dealer who provides that service sees their customer come back.
Good luck
Marc