Revell produced a Henry J in 1/24 scale but as a gasser (drag car). At least two editions of the car were made, the first being in a green and a later version in dark blue. There are usually several of the later version on ebay.
Several manufacturers produced resin Darrins, 1953 Manhattans, and Willys Aeros - all in about 1/25 scale. The quality varies on these.
I've also seen HO scale resin 1949-50 Kaiser kits on ebay.
In assembled models, Yat Ming produced Henry J and 1953 Kaisers in metal in 1/18 scale. There's usually a few on ebay.
Goldvarg, Conquest and Brooklin are just a few of the companies who made Henry J, Darrin, and 1953 Kaisers in metal in 1/43 scale. Check ebay as well.
And, Banthrico produced a 1953 Kaiser bank in 1/25 scale.