I've been tinkering with Hy and am curious as to how hard it would be to bundle with Pythonista (I haven't really tried running it there yet since I've had very little free time, but it seems feasible since it's pure Python as far as I can see) - and by that I mean adding corresponding syntax highlighting and support for running .hy files as well.
It's really well integrated with the debugger, and I think this would be an interesting way to cater to the functional programming crowd (as far as I know, there are no modern LISPs running on iOS, at least nothing with this potential).
A little follow-up on this: I can almost get it to run (like I did with clojure-py, I needed to provide my own copy of py_compile), but it crashes Pythonista at the REPL. I suppose there might be something else missing.
To get it going, I synced the hy and rply folders to Pythonista and used this little script:
from hy.cmdline import run_repl
...after entering a single expression like (import json), Pythonista crashes.
A cool recent webcast on the topic of hylang... http://podcastinit.com/hylang-developers.html