HI Skywalker, thank you for ordering!
You can buy a short sword (gladius) already in the free Demo Version: Not from the smith in you home village; but the smith in Cattanford will produce one of these for you.
As to the Roman shield, yes, you'll have many opportunities to capture these in the Full Version.
However, in my opinion, I think it's not such a good deal for a single fighter, because its huge size will greatly impair your dexterity. In my opinion, this type of shield is mainly useful for a row of soldiers standing in a file, one closely next to one another, each covering both himself and part of his neigbor with his shield, everyone pointing their spears at the enemy, and this whole troop advancing, mowing down everything in its way like a steamroller (Greek idea; Phalanx). In such a combination, this type of shield really makes sense, creating a sort of solid front, and thus rendering the entire troop fairly invincible to attacks. But for a single fighter I don't think it's worthwhile.
As to other kinds of Roman armor to be captured in the Full Version, what will be much more useful to you is the Roman segmented cuirass, which weighs far less than a chain mail, doesn't impair your dexterity much, and offers great protection. Also worthwhile is getting a Roman iron helmet (more solid than Bronze, and better designed than the Barbarian helmets, with additional protection for cheeks and neck).