in your image editing program it shouldn't be a problem to create bigger images. you can scroll. and then do some panel scaling code. i don't know what your requirements are but i wouldn't make the resolution of the panel images too big. i think 1024x768 or 1280x1024 is a good panel resolution.

...and you could get a 21" 1600x1200 or 24" 1920x1200 lcd. most crts can't do more either.