Well, I did talk to Armando at borrowlenses.com and this is what he had to say:
“Hi Kevin,
Thanks for the e-mail. For the BMCC, there are a lot of factors to keep in mind. The fact that it is EF mount will limit you to only Canon lenses if you want compatability between both a DSLR and that camera, so I think a 7D would give you the best quality with the lenses I think would work best for you.
https://www.borrowlenses.com/product/Canon_7D
I’m recommending this one because it takes EF-S lenses as well as regular EF lenses. The EF-S compatability would work great with the BMCC because the lens that we most commonly recommend with the Blackmgic is the Tokina 11-16, which is an EF-S lens built for cropped sensor camera bodies. Since the BMCC has a 2.4x crop factor, finding a good wide angle can be difficult. The Tokina fits in nicely with both the 7D and BMCC as far as wide angle range is concerned.
https://www.borrowlenses.com/product/Tokina_11_16mm_f2.8_canon
If you want a little extra range on both camera, I can recommend the Canon 16-35 f/2.8 as well. Very solid lens.
https://www.borrowlenses.com/product/Canon_16_35mm_f2.8_II”
I hope this bit of information may be of use to others looking for a DSLR to go with the BMCC.