The 75426 Millennium Falcon does not come with any SMART bricks, the two SMART bricks I used are from 2 other sets.
To save on brick sorting time, you can leave out bag 1 and 2, as my design changes starts after step 78 on bag 2.

The model is 23.3 cm wide, 27.7 cm long, 9.0 cm tall
Or 9.2 inches wide, 10.9 inches long, 3.5 inches tall

The original 75426 set focuses heavily on the Smart Play system with a beautiful interior with easy access. While this creates an interactive experience, the exterior really suffers in terms of the massive red gap behind the cockpit and the overly chucky proportions in the hull and mandibles. What is also a bit ironic is that the SMART brick itself is not included in the set. Like many others, I ended up purchasing the $100 AUD / $70 USD LEGO Star Wars TIE Advanced as the cheapest way to get the SMART brick and unlock the full play functions. I suspect LEGO may eventually release the SMART bricks as standalone items after this initial wave.

I also have to give credit where it is due. While I think the SMART Play system compromised the exterior appearance of the model and was quite expensive for what it offered, my 6 year old son was completely enamored with the LEGO SMART Play ads. I kept catching him watching them on repeat, and he absolutely loved it. Seeing his excitement ultimately convinced me to invest the time into designing this alternate build.

My goal was to improve the display value of the Falcon without compromising the play features, using only the pieces from set 75426.

The Falcon was slimmed down by reducing the height of the fuselage and mandibles by one plate. The slopes of the exterior panels were adjusted accordingly, improving the overall silhouette without affecting playability.
The mandibles were updated to be more pointed by modifying the panel doors so the end tile can slot into the trunk space.
The maintenance access bays were repositioned to better match their correct locations.
The rear engine vents were moved closer together by redesigning the panels they sit on, preventing them from looking too small when spaced apart.
The infamous “Smart Hole” behind the cockpit was closed using round and curved elements. The top panel can also open, allowing Han to sit in the back seat behind Chewie and completing the tandem seat cockpit.
The red laser cannon trigger was relocated inside the hull and connected to the same axle that activates the engine thruster sound. This hides the mechanism inside the model while allowing two functions to be activated with the movement of the axle knob.
The grey axle connector was moved next to the knob so it blends in better, avoiding the visual distraction caused by the original red connector.

A number of other adjustments were made throughout the build to support these changes. The Millennium Falcon remains structurally solid like the original set, easy to pick up and swoosh around while making all the appropriate spaceship noises, whether powered by SMART bricks or your own throat.

Overall, I believe this alternate build achieves a good balance between display accuracy and play value. Hopefully LEGO continues developing SMART Play sets in the future, because good play features and good looks do not have to be mutually exclusive.