For a frame, I’d look for one from a Ford dealership in your hometown. Try to get the vintage of your car. I’ve looked for years for one the town I grew up in. For now I’ll use the record speed that got me into the Bonneville 200 MPH Club. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

A little history on License plate sizes.  Many states, California included have used different size license plates over the years.  The automobile manufacturer's wanted a standard size so they could make the bumper or body openings standard to fit one size plate.  In 1956 the US standardized the plate size used in any state or territory and that size is the one we use today.  It also makes it nice for the folks that make license plate frames not to have to make them in multiple sizes.  

Try this guy. Go down to License Plates and click, then down to the listing of plain metal plates. I’ve bought a handful of stuff from him, it all been ok. Some of the odd stuff is worth browsing just for a laugh.

http://www.taillightking.com/

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

A quick Google search shows a number of places offering custom frames for reasonable prices.   The toughest part is coming up with something worthwhile while still not offending anyone to th point they damage your car.  FWIW, the frames on my SLK say "because my friends all drive Porsches" which gets favorable comments.  
Good luck,
Don

I like the Y-Blk plate.  However I already have the plate with just a random number assigned.  I don't know in this state if they have vanity plates for historic vehicles.  

I have looked at Ebay until my my eyes go blurry.  Thousands to chose from.

I
I would suggest looking at ebay.  They must have all sorts of license plate frames (I admit, I haven't looked) and you may find one you like.

For my 54, I bought just a plain frame that goes around the plate, maybe about 3/8". I prefer plain things, like to show  the car, not crazy about add on stuff.


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

I believe the license plate size on the '56 is the same size as today.

The problem with the latter is that you don't want someone getting offended and keying your 'Vic.  I would run with the Crown Victoria one (maybe post a pic) until you find something you really like.  

I had an In N Out burger license plate frame for my Model A but decided it just wouldn't have worked.  

Deleted

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Is it a standard size (called Federal, I think) or an odd size like WA was till 56 or 7?

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ