I asked Dave Hollins about these guys about a year ago, here's his answer :
"The 1778-9 unit wore a dark blue faced ponceaurot tunic with yellow buttons and the same was used in 1790, except the jackets were supposed to be hellblau (bright blue) in 1790 before reverting to dark blue in 1791 (ie: probably dark blue all the time).
In the following 1790s, it was grass/dark green with black facings (yellow buttons changed to white in 1794). Obviously, they needed a new unit when the existing Staff Dragoons became 9LD in 1798, so various men were drafted in from various cavalry units. They were supposed to be kitted out in dark blue tunics (probably old ones recut to the 98 pattern) , but an HKR order of 1799 puts them in the pike grey jackets faced krapprot with yellow buttons.
In 1805, it is Pike Grey with Krapprot facings and white buttons with Hussar saddles.
In 1809, it is white tunics with krapprot facings and collars, but white turnbacks and Chevauleger saddles, although an official order acknowledged that the allocated men could only be supplied with krapprot material for the facings/cuffs (they seem to be a mix of Dragoons and C/L). "
"In 1809 the staff infantry wore the same uniforms as the staff dragoons, but they are a bit different earlier on.
1792-1801: White uniform with no facings etc. and just yellow buttons, although the officer had Pompadour Red facings and cuffs.
In 1805, they are quite similar to the cavalry – Hechtgrau tunic with Krapprot facings and yellow buttons.
In 1809, the Staff infantry were drawn from the Grenzkordon (that's the border guards all around the empire), hence the white uniform with no colour on the turnbacks, so they just changed the black cuffs and collars for Krapprot and they were definitely in shakos."
Hope this helps,
Iannick
clashofempires.ca