"Continental light infantry" Topic

Anyone can tell me of a light regiment which wore bicornes like the regulars?

Whenever troops went into battle they would send out skirmishers who were troops from the line. Light troops were introduced in 1778, so before that light troops would be picked men from the regiment.

The "light infantry" units were primarily ad hoc, temporary units that were organized for limited periods of time. The light infantry units created in 1781 under Lafayette's command were outfitted with special headgear, but before that they wore whatever uniform they had.

Morgan's light corps at Cowpens is probably a good example. The unit was drawn from the remnants of the Maryland and Delaware Continentals that survived Camden. Before heading south the records indicate that the Maryland continentals were issued "hats" but there was no reference to "caps" issued. In fall of 1781 the Camden survivors were issued blue faced red short coats and hats, again no caps are mentioned. If there were any caps in Morgan's light corps in early 1781, they would have been over a year old.

Bicorne hats were not worn during this time period. As others said, the Light company in Continental regiments is something of a mystery since they were often picked men operating as Lights, such as Maxwell's command at Couch's Bridge.

Or Dearborn's picked Lights at Saratoga. Best guesstimate is that he picked his men from the commands he was familiar with.
Not much else is known.

So I just paint them as normal continentals then? drawn from different units like grenadier batallions

That would be the consensus for much of the war. The later light battalions (also converge from other units) may have had some distinctive hat. I want to say that Lafayette bought them some, but those might have been captured on the way over.

The picked men was much a crze in the Continental Army, as demonstrated by the mixed force sent out under Lee at Monmouth, though they were not Lights, just picked men.

To stretch some of my CL units I sometimes mix in a stand of Lights (with caps), but I am not aware of the Light companies' role in the field being any different from the hat companies.