I've never seen any info on grafting chaenomeles. You may be the first to have this great idea in which case you will need to do some trials to see what works.
Generally grafting works with members of the same genus. Some plants can be grafted onto other related members of the family. eg pears on quince stock., Eremophila on Myoporum stock.
You should have no problem grafting your chaenomeles onto any other chaenomeles but, as they are naturally suckering shrubs you may find it more trouble than its worth to maintain your single tall trunk,
You could try other quince species like Chinese quince or European quince to see if they are compatible. Chinese quince would be ideal as it grows quick and doesn't sucker. European quinces sucker from the base so not ideal.
Then try some other members of rosacea family like pears to see if they are compatible.