David
As I see it 2018 models will pitch you against the Bosche Powertube which gives a lovely intergrated look. Can you not intergrated the battery more to compete against that? Otherwise you may be a step behind on "looks".
I'm sure you've seen the 2018 Haibike and KTM intergrated offerings. I do see you now moving up a class into that range.
Personally I'm not that keen on the fully integrated battery design that you are talking about.
I don't relish the prospect of having to remove a potentially wet and muddy battery housing, or even battery in wet muddy UK conditions, and then there is the prospect of having to store an even longer battery into the Camelbak for rides that require two batteries.
For me the practicalities of semi integrated battery such as on the above bikes and on the 2017 KTM range, that load from behind the downtube rather than in front where it could be vulnerable, outweigh the potentially better appearance of a fully integrated design. In reality an eMTB will always look like an eMTB, so unless weight distribution is a deciding factor in the design, I'm in not in a great hurry to change to a fully integrated design.
edit.. I should add that I haven't tried the fully integrated design, so my opinion is based upon photo observation only, and perhaps the reality of such a system could be different. In the case of the Levo though, my observations are very much correct.