Correct - you cannot just link the charts together graphically. All the sectionals are projected with a Lambert Conic projection, but each with different values specific to that area of the country. (BTW, the neat thing about this projection model is that great-circle routes are all straight lines...perfect for planning your route on paper with a ruler...but not really as important on our device. Mercator or other projection types would be fine). Anyway, all the charts would need to be re-projected to a new model in order to properly stitch them together. This is not too difficult to do in itself, but there would be a lot of manual work to ensure the seams look good, and this would need to be re-done every month since the sectionals keep changing. So it adds up to a lot of work.
Also, we've had a lot of comments from folks that like having the full chart available, including all the information on the border. Because of the quantity of data involved, this would be an all-or-nothing change: We could not easially support both stitched and unstitched charts. So let me do an informal poll: Who likes indipendent charts, and who wants a uni-chart?
Thanks!
Walter