I haven't heard of anyone working on one, unfortunately (I can see why - Sony basically more-or-less sits on the license, keeps it from seeing appropriate releases on suitable hardware, and their track-record suggests that they are a lawsuit-happy bunch, which is something most people wouldn't want to risk dealing with). That said, I know of some clones - a search for Lemmings ought to bring them up. Ones I can think of off of the top of my head include "Zomblings" and "Mechanics Touch".
There was also
Droidlings, but I don't know if that has continued progressing or not.
I seem to recall that Sony released a crippled, paywalled "port" of the PlayStation Portable version, as well, but I have no idea if 1: that's still available, and 2: if it's available to all Android users or just those using Sony hardware (it doesn't come up in any searches for Lemmings, for whatever that's worth).