Look around and when you see a horse farm ask them if they know anyone who has any for sale. Most people with horses know others with them too!
A chestnut (A.K.A Sorrel) horse crossed with a cremello will always come out with a palomino foal.
The ApHA (the Appaloosa Breed Registry) will accept in it's registry any foal with ApHA, AQUA (Quarter Horse registry) or Jockey Club (Thoroughbred Registry) and is still considered a full Appaloosa.
Palomino is a color, not a breed. A horses color doesn't really affect the way a foal is born. This menas that a palomino colored foal is born in the same way that a foal of any other color would be.
Most likely would be cremello, palomino, chestnut (sorrel) or another buckskin.
Palomino
Typically a cremello or palomino crossed to a bay or black horse will produce a buckskin foal.
palomino
Cremello, White, Black, Palomino, Brown, Brown Draft Foal, Cria, Zebra Foal, Grey, Overo, Tobiano, Leopard Spotted Foal, Chestnut, Bay Blanket Foal, Strawberry Roan Foal, Blue Roan Foal.
Palomino foals can range in color from creamy gold to nearly chestnut looking, where the mane color in the same as the body color but grows out the signature white as the foal coat sheds and the mane grows out.
The foal's base color will be chestnut. 50% chance of palomino. The sooty factor may or may not be present.
Breeding for a Palomino foal is not an easy task since the coloration is often an 'accident'. One reliable method is to breed a Palomino with a light Chestnut of Eastern blood.
Sometimes it is true that breeding two palominos will result in a cremello foal. When bred together, two palominos can produce: 25% Cremello 25% Palomino 50% Chestnut
Without knowing exact specifics about each horse you can reasonably expect a 50/50 chance at either a palomino or a cremello foal.
The color of the foal will depend on their parents exact genetic coding, without this information it would be very hard to give an exact answer.