After extensive research across all possible options, I choose the custom Flume. I opted for the Manitou Mastodon fork and upgraded to the GX drivetrain to get the lowest gearing possible, with the smallest chainring for maximum torque.
I am so pleased with the quality of the frame and the overall product - this bike is a fantastic value and I don't regret the money spent at all. The 27.5 wheels on 65mm rims are perfect size to go up to full 4 inch fat tires or down closer to 3 inch - I've now run the full scale and I love being able to swap out for exactly what I need, summer vs. winter.
I've turned it into all season explorer, ready for everything from local trail riding to multi-day bikepacking. I also added a Thudbuster suspension seatpost, dual sided clip pedals, a Sonder Confucious handlebar and ergo bar ends. With a frame bag and a seat pack I can go just about anywhere any time of year! Borealis also built me a 29" x 45 mm front wheel upon request, so now I'm running a hardtail fat bike mullet!
Lots of fun - so many options - that's what I love about fat bikes. This bike seems to be the perfect and affordable platform for whatever I want to dream up, and so far I've been able to ride much steeper and gnarlier terrain than my full suspension 29" ever did.