ive already thought about asking for something like this.
the only way i see it could be done is using a pixel shader. im not sure how i can explain what you need to do without a picture so here
youd need to map the layout area into a virtual hemi cylinder, and map the sprite as a virtual cylinder (or sphere depending on what shader youd need), then youd need to make the sprite reflect what was on that hemi layout. things farthest from the sprite would be extremely squished, ect like youd expect on a rounded objects reflection. then youd have parameters like reflectivity, and specularity. it would be pretty GPU heavy tho.