Hi, first time posting, long time lurker to this thread. I've been collecting this collection from the first one and I look forward to looking in here for glimpse of future models. Thanks to those finding out the info.
With regards to the T55 tank and little Nellie, I've got a couple of ideas. I'm sure like others, I've been wondering what to do with them and how can I get them in cases with a background like the others. I'm thinking of playing with the image below in Photoshop to remove Nellie to create a background and I think I'll order a second Land Rover Defender for a sandy effect base and just replace the name.

Now the tank is going to be a more creative. When I saw the Volga model, I had an idea. I'm thinking of looking out for a long display case the same width as the rest of the models. A case for a 1:43 lorry or something, just for the cover. Now I'm thinking of getting an additional 3x Volga models for the bases and cut the ends off and glue together (keeping hole in middle for a screw) and fill between the gaps with filler and paint to match and blend in. This hopefully would give the correctish base and cut to length to fit underneath the long case. This does sound a bit expensive and a long way round, but could look good when done, hopefully. I just need to work out the background to wrap around it.
Anyone else has any other ideas or am I on the right path? I know nothing about modifying models or the case bases, but these two models have been bugging me for not being the same as the rest of this great collection. There has been some great homemade modifying of models in the thread previous. I just hope the Dragon tank comes with a case.