Sure. Replace your WF-7720 with a WF-7720.
It can take a CIS, and 7720s can still be had new. I still use my WF-7720, though I admit I use it mostly for 13x19 posters only. If I were to put a CIS on it, though, I would also (carefully) install a chipless firmware too. I use refillable cartridges on my 7720, and because they are mounted on the print head and get tossed around a lot, the chips sometimes lose contact and I have to reset the cartridge.
For 11x17 page sizes and smaller I use my MFC-J6945DW. It doesn't have an available CIS, per se (and I wouldn't use one on it even if it did), but the printer does use nice large front-loading cartridges and you can get refillable ones. So much better than trying to use a CIS on a printer where the cartridges are on the print head.