Northumbrian Painting services have just released a brand new Portable Cabin kit for the 7mm Market, made from an MDF kit. They had these on show at the Kettering show at the weekend and they were flying off the stand to the point where I believe they'd only got the demo one left!
A few details on the kit are below provided by NPS;
O Gauge Porta-cabin
Width - 24cm
Depth - 6cm
Height - 7cm (includes feet risers)
Comes as a comlete kit with acetate for the windows
Door can be open or shut
These kits are now available for purchase over on there website below;
I've also attached the images provided below so you can see one ready built.