If you could avoid daily use,you could try some RCs,some of them seem promising and are known to mimic amph effects.Im currently thinking about trying out a couple of them,but id suggest you limit your use to 1-2 times a week tops(since you wouldnt want to replace one drug with another,plus i dont think that long term RC use would be ideal).
If you could do that,then maybe drink some booze or take a benzo for a night or two,smoke some weed,you know,just mix it up and break the habit(of ice).
Then again,you could try the ultimate tolerance "decreaser",abstinence for awhile.See how that works out,give ur body a break,maybe give urself some time to recover and be able to enjoy the meth once again.