As well as working on the Austrian Grenadiers, I also plan on completing (well starting) The Vienna Freikorps which fought with distinction during the 1809 campaign. I have four of the six battalions that were raised.

The uniform of the Austrian 1809 Vienna Freikorps (Volunteer Corps) was simpler and less standardized than that of the regular army, as they were hastily raised volunteer units. For those raised in Vienna and Lower Austria, the basic infantry uniform usually included a grey jacket. This grey was similar to the color worn by the Austrian Jäger (light infantry), though the style varied and sometimes resembled a civilian coat or peasant smock. The distinctive color for the Vienna and Lower Austrian region was red, used for the facings on the collar and cuffs of the jacket.

The headgear was typically a black “Corsican hat” (Korsikanerhut), a round hat with one side of the brim turned up. It often had a national black and yellow cockade or a pompom. Due to local supply, variations were common; some units received regulation-style shakos, while others wore civilian hats with a cockade. Equipment like cross-belts and cartridge boxes was usually made of black leather, similar to Austrian light infantry. The lack of proper uniforms resulted in mixed items; while officers wore complete regulation outfits, the rank and file often used their civilian clothes with just the essential equipment added.

It is worth noting that the six battalions of the Vienna Volunteers (Freiwillige) were generally better equipped than the basic Landwehr militia, especially the First Battalion. This unit was raised from the upper classes of the city and was able to afford to supply its own uniforms to a higher standard. They followed the basic pattern of the grey coat with red facings, but as a marker of their volunteer status, they were sometimes permitted to wear pointed cuffs instead of the standard round cuffs found on the ordinary Landwehr coat. In contrast, other Vienna volunteer battalions, such as the 3rd, wore a simpler uniform that was closer to the standard Lower Austrian Landwehr issue. The wide variations and non-regulation items used by the Freikorps and Landwehr in the 1809 campaign are well-documented, making it a challenge to pin down a single definitive uniform for every corps.
One web site shows the first battalion with white trousers.

I have decided to paint the first battalion as above with the 2nd to 4th as the Austrian Jaeger but with red facings.
The figures are from Elite Miniatures Australia – here, here, and here.

Undercoated and ready to start on.