I have a faint memory of a modpack i played on that allowed me to craft those all sided wood logs. i'd expect that mod would allow you to craft the all sided sandstone slabs (my favorite block of all time)
I don't know of any such mod, but that is a pretty easy thing to do. However, if you simply want to replace the old blocks with a new better looking one, you could make a resourcepack that changed the texture on one or more blocks to better fit your preferences. Minecraft 1.8, with its blockstate and model system, would even let you change the shape of these blocks to have 3D bricks or inset edges.
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My mods: Base Metals, Power Advantage, Steam Advantage, Electric Advantage, Minecraft Mineralogy, Dr. Cyano's Lootable Bodies, Dr. Cyano's Wonderful Wands & Wizarding Robes