Floyd-style Bass Tremolo
As far as I know, Floyd Rose has never made a tremolo for bass guitar. However, there are examples of custom designs which resemble the Floyd Rose style.
Above is a bass player that goes by the name of “Foley” and was the bass player for Miles Davis from 1987-1991. The bass was custom made by “A Basses” and the tremolo was built custom by Harry’s Metal Shop in Queens. The builder says:
“I met Foley when I was living in NYC, he was playing with Miles Davis. Foley wanted A blue 4 string piccolo bass w/whammy bar! Not an easy task at the time…that bridge was not an off-the-shelf item, it took many subway trips to Harry’s metal shop in Queens to get that customized bridge right! Foley’s bass is the closest I’ve come to making a guitar….”
Above is Foley playing the bass. Skip to 2:25 for close up shots.
Above is a more recent video from 2014 showing the same style bass tremolo but with a different bass guitar.
ABM Bass Tremolo
At one time, another company by the name of ABM out of Germany made a similar style bass tremolo as shown above. Perhaps you can ask them to custom make you one?