In some cases, with certain products, this is defnitely possible! For example digital print products, such as postcards and stickers can be cut to pretty much any size within A3, so we'll be happy to accommodate requests like this. Some products such as our garments are direct from suppliers, so we can't customise the actual garment, only the print, however we can remove the manufacturer's label and customise the inside neck, so it is retail ready!
If you have any specific requests for our products, please feel free to email over and we'll be happy to look into the feasibility of this! Just drop us an email with some details of your requirements to firstname.lastname@example.org