No, rightly so.
I'm a political scientist, I see immediately why someone would like to type arabic on a latin keyboard.
I use the compose key solution only for a handful of specific letters which are not part of latin1 or not on my keyboard - turkish i dotless, polish l, french accents - stuff like that.
If it comes to a single character or maybe two in chinese or japanese, I use Unicode code point intput with Ctrl-Shift-u.
Everything which somehow resembles an entire "word", I start scim for with a real input translation. First it seems a bit inconvenient, but one gets used to it.
The only language I'm thinking of connecting an entire different keyboard is for russian.
Or back to pen and ink.