Imperial Armour Volume Two 2nd Edition, Warmachines of the Adeptus Astartes.
Are you thinking of running some repressors? Do it. You will not regret it. I have run an armored spearhead of AV13 SB/HF loaded with sisters straight into midfield on turn one with a lot of success, even in last edition. It is by far one of my most favorite vehicles in our armory.
There should also be some experimental rules in the downloads section of Forgeworld's website. While it is not the same, it is close enough not to be a big deal. My book is upstairs and I am lazy, but if I recall correctly. Three bolter girls can shoot from each side and one can shoot any weapon out of the top. I could be wrong, though. If all else fails, just know that there are FOR SURE three bolter fire points on each side.
Also...get it. It is amazing. If it is a bit much, it is easy enough to drop a dozer blade on it and scratchbuild the top.