The Ilya Muromets bomber figure will be in the Marketplace in a few days.  Meanwhile I've been building an Add-on product.  Before it became a bomber, Sikorsky's four-engine aircraft was conceived as a commercial airliner.  I haven't seen any drawings of it but there are several photos and at least two (conflicting) textual descriptions.  I have some restrictions because the add-on will use the bomber air frame, so, as the bomber model doesn't represent a particular bomber configuration, the liner will be just reasonably representative of the actual aircraft, but it will render it true to the historical photos.

 Here's an very early render of the add-on fuselage and interior.

Two views of the commercial transport fuselage showing the exterior and interior.  Yes there was an open platform on the roof.  There is a photo of the liner landing with two people standing on the platform!

The empty space in the foreground is actually reserved for the Ilya Muromets cockpit.

Here's a DAZ Studio render of one of the paint schemes.

Almost ready.

Now in the Marketplace:

https://www.renderosity.com/marketplace/products/162294/ilya-muromets-commercial-transport-add-on