If all you need is a garden-variety ssr, look at Crydom's stuff.
Newark sells a lot of it. I know they have some units with 120vac
trigger voltages, don't know about DC at that level. Most of the DC
ones I've seen are 3-32v. I don't understand the current-limit part.
Regular ssr's usually current-limit by failing. :) If you want
variable chopper, look at SSAC stuff.