I have made my own decals in the past for vehicle conversions, you can do it yourself with special decal paper and an ink jet printer, it's
not hard to do but some colours do not show up very well. There is a firm that will do them trouble is I have lost the name of them,
if you wanted to do them yourself it is best to use an ALPS printer but when I was doing my own they were not cheap and now I
don't know if they are still readily available, hope this helps a little bit, if you want to know more just pm. me and Iwill try and help further.
Chris