Emma J is probably the one to ask. If anyone's done it, she has! Or she would probably have some very good ideas on how to do it.
Ahh thanks for the vote of confidence
Yes I have done it, I created all the wallpapers you can see in my rooms. I think it's one of the main features of any of my rooms or houses that I sell, that I've coordinated the wallpapers and flooring to go with the furniture. I'll be honest it took a lot of time, effort and hard work getting the right templates made. It all depends on what software you use.
I've only got very basic stuff just windows paint and excel. I started off with scans but found my software would not print it out 1:1 so through trial and error and printing out lots of outlines I have a basic template for all the wallpapers for 5300 and 5302, which work with my settings on excel and my printer. From there is just a question of filling in with what ever patterns you like.
Add borders, change colours make up tiles etc. It takes me anything from an hour to five or six, to do one set of wallpapers depending on how complicated the design is. The tiled paper in Jones the butchers was made up entirely form pictures of real Victorian tiles, photographed, edited and shrunk to fit my design.
Once you've got your template sorted then it's just a question of how fancy you want to go.