This brick tile already exists but it does not exist in a format that supports being solid and able to support a portal. The snow series of tiles does have this and it supports portals and is solid. Don't confuse this with the brick tile on the top row of tiles as that has a white border along the top (Intentional, for making solid brick blocks stand out against a brick background) making it fugly to build with.
I'm unfamiliar with adding my own custom graphics to the game and even more clueless about how to adjust the properties of tiles.
