I and II are translated but apparently the translations are terribly glitchy and barely playable. 
Untrue. Both SMTI & II are fully playable if you're running the translations on romhacking.net.
Have you played them all the way through? I've read on other forums that they become quite glitchy in later parts of the game, some alignment paths and endings are completely unattainable. Moreso in SMT I than II. I've read enough of these accounts to prevent me from getting them made on repro carts.
In SMT I apparently you have to remove the patch from the rom to get through certain parts or it will just hang. You also can't buy guns or beat the Law alignment...
I mean it is the internet and it could all be BS, but there seems to be more consensus towards them not working, at least not entirely.