if so, any pics?

Short answer-- yes the S-65 was used to tow the earlier version of the B4 howitzer. The Trumpeter kit has a flyer in the box displaying the B-4 as a recommended towed artillery piece for the S-65. As for photographic evidence, there are a few photos of the S-65 towing the B-4 howitzer in the Tankograd Publishing book _Tyagatshi: Soviet Full-Tracked Artillery Tractors of World War 2 in Red Army and Wehrmacht Service_.

As I do not have the rights to copy those photos on-line, you will have to search through other means.

Yes, these tractors were used for towing of B-4 howitzers too.
This howitzer could to be disassembled on two parts for transportation:
- first part - barrel with all gears,
- second part - whole running gear.
The barrel was fixed on special transportation "chariot" on base of T-26 light tank.
Then both parts could to be towed by "Stalinets" tractors.

Does anyone have a photo of the T-26 carriage used to carry the B-4?

Take a look here :

http://waralbum.ru/28896/

Just click on "1280x792" to enlarge the pics. There's a thumbnail for a second picture at the bottom of the page.

HTH

H.P.

Barrel + T-26 carriage + "Stalinets":



Rest part of B-4 - the running gear:

Just to clarify, photo evidence indicates that it was not required to dis-assembe the B4 howitzer in order for the S-65 to tow it. There are photos of the S-65 towing a complete B4.

thanks