Negative voltage current limiting
It should be symmetrical to the original but not like that. The circuit you need is following:







simulate this circuit &ndash; Schematic created using CircuitLab

Decreasing voltage of V1 will make BE junction constant at cca 0.6V, what means BJT will be in active region. As \$I_B\$ increases so do the gate voltage and source voltage, therefore \$V_{GS}\$ will be constant as well as your drain current.