The T.I.E. starfighter was the first fighter to utilize the famous "ball-shaped cockpit flanked by vertical wings" design, and seemed very similar in terms of shape to its descendants.
The T.I.E. could be traced back to a courier design produced by Raith Sienar's Sienar Design Systems before 32 BBY, the ship which became Darth Maul's Scimitar—although Scimitar was a large, sophisticated runner rather than a compact, mass-produced starfighter.
The next stage was the Advanced Project ship, a starfighter prototype design, the latest and smallest of which Sienar was building in 29 BBY. Designed to escort cargo freighters on the Outer Rim Territories for corporate clients, these fighters were built to deploy into combat from tight-packed launch stacks in ordinary cargo-holds. Visually, they abandoned the blade-shaped forward hull of the Scimitar, and had broad vertical cooling vanes at either end of a twenty-meter wingspan, and a compact, sphere-shaped crew-compartment in the center: the essence of the T.I.E. design had arrived.
Some early Advanced Project ships might have flown as early as the year following the Invasion of Naboo, as several ships with ballshaped cockpits and vertical wings were observed at that time in an important Republic system along with different types of warships.
It would be another seven years, however, before Sienar revealed the final component of the T.I.E. design, the SIE-TIE twin ion engine, a powerful and highly-innovative propulsion unit which was officially endorsed by Republic Sienar Systems shortly before the Battle of Geonosis and the outbreak of the Clone Wars. This paved the way for the final starfighter design, and it meant that Republic Sienar Systems was well-prepared when the Republic called for a new, standard mass-production starfighter during the Clone Wars.
Although the new engine design was incompatible with established hyperdrive, life-support and shield systems, the T.I.E. was incredibly cheap, insanely fast, and could stack tightly in converted cargo holds or external launch-racks aboard the Navy's existing line-combat ships. By the first weeks of the New Order, T.I.E. fighters, already known to front-line personnel as "TIE fighters", were deployed aboard ships, such as the Victory-class Star DestroyerStrikefast. Presumably, they were also the TIEs used aboard the Eye of Palpatine in the following year.
It may have been the ability to give a fighter capability to ships like Dreadnaughts and Carracks that ensured that the T.I.E. won the design contract; but at the same time, it can be noted that Kuat Systems Engineering's rival designs, the Eta-2 Actis-class interceptor and Alpha-3 Nimbus-class V-wing, looked suspiciously like knock-offs of Sienar's technology and designs by their leading corporate rival. Although these rival craft gained fame during the Clone Wars, they became increasingly marginalized in the years that followed, and in 9 BBY, Sienar bought up the remnants of the entire production series from Kuat.
By this time, the original T.I.E. had evolved into the TIE starfighter, which would continue in the form of the TIE/LN starfighter, the dominant starfighter of the Galactic Empire, and although TIEs proved vulnerable to shielded and hyperdrive-equipped Rebel snubfighters during the Galactic Civil War, the design proved to have immense capacity as a platform for modification and upgrades: advanced variants of the basic T.I.E. technology, such as the Clawcraft and TIE/D Defender would still be among the most potent and capable starfighters in the galaxy fifty years later. Over a century after the Civil War's end, the Predator-class fighter carried on the legacy of the T.I.E.
The opening frames of the story Nomad in Star Wars Tales #21 shows a TIE-like ship as part of a military presence in a "grand and important" system, in a story set six months after the Battle of Naboo. The ship has notably eight sides to each side-panel, as opposed to six on a TIE fighter.
It is possible to integrate these ships into the known evidence for the backstory of the T.I.E and TIE designs, which begins with the Advanced Project ship first mentioned several years after Naboo, but which was developed from older models. The TIE-like ship shown here is seen alongside capital ships similar to Acclamator-class assault ships, which are otherwise first recorded a decade later. This is a relatively small problem.
With the scene being shown in real colors, as opposed to color-tinted panels (blue or gray, used in flashback sequences), it's more than likely taking place in the time-frame of the story. The only flashback sequence shown in real colors takes place in the issues following this, and have no connection with this scene. Interestingly enough, this flashback featured Kuati-style warships similar in appearance to Acclamators, so this type of ship-design was present at least in the decade before 32 BBY.
Moreover, it would not be unreasonable to have an Acclamator predecessor present as well, since the class was meant to be a military transport, and Rothana Heavy Engineering could easily have decided to upgrade a tried and true transport-design for the Acclamator-project, rather than spend money and resources coming up with a radically new design.
Another important flashback shows an interstellar Jedi transport nearly identical to the LAAT/i gunship, further solidifying the presence of vehicle-designs that would only play a role on a galactic scale decades later. Therefore it's believable that a T.I.E. fighter predecessor, or possibly even an early Advanced Project ship design, was performing test runs years before being officially described (it would be a logical company decision when dealing with a risky endeavor).