If you want to renovate a classic cycle frame that is out of production, Nick Tythecot of H. Lloyd Cycles may be able to help with transfers (decals).
H. Lloyd Cycles, PO Box 133, Penrith, Cumbria, CA10
Lloyds supply original, reproduction and waterslide transfers to many bike shops. They carry a stock of about 300,000 transfers for classic bikes, most of which are long out of production. They have about 500 master transfers, originals from different makers. These are not for sale of course, but they can be reproduced.
They will want to know the make, model and year of your bike if possible. Many makers changed their decal designs for different years, this way you could well get exactly the right transfers for the model and year.
If the original samples are not available they may still be able to reproduce transfers based on the originals, though intricate designs take longer to make and can be costly. It's best to e-mail them and tell them what you want.
They have an extensive list of transfers on their Web site.
Yellowjersey in the USA supplies Holdsworth decals: