No because all monocots are not graftable. The point of grafting is one plant healing over a piece of other plant. Palms dont heal when cut so it won't work.

I really wish that you could! But I think the only way you could manage to cross palms like that would to get very technical and change the DNA of the cells or seeds somehow in which you could almost cross breed 2 distantly related palms.
I do think that it is possible to cross palms such as a pindo and a coconut, but not naturally so it would require doing things with the seeds which would probably cost too much money to make a profit.
It is something really interesting to think about and I dont know much about altering seeds and DNA, but I think that you could do that with enough money. Not sure if it would work on a fan palm like a washingtonia and a feather palm like a coco but maybe something like a pindo palm and a coconut palm could be done and definitely create a cold tolerant, tropical looking palm (I wonder what the fruit would be like since both of these palms are edible).
But when palms get cut off from the trunk past the growing point, it will be pretty similar to graphing 2 telephone poles together!

Hopefully someone will know a little more about the inner workings of a palm tree than me but thats my theory!
Good luck!
-Alex

Genetic enginering is amazing. Alot of our food is enginered. For example corn is resisten to the european corn borer because genes from a certain bacteria were inserted into corn dna. If you had tons of money and access to a genetic lab you can take a coconut palm and take traits from a pine tree to make it hardy to -50. Add traits from empress tree to make it grow a foot a year. Its all possible but costly and time consuming.