Uncle Dave's summary was on the mark - as an added option to think about, maybe an external organ module like the Roland VK-8m would be the answer. Getting a decent piano sound out of an arranger isn't too hard but finding one with actual or virtual organ sliders would limit you to very few models. An external organ module would free you up to select a wider range of arranger or other keyboard options, plus the VK-8m happens to sound pretty good IMHO.