Zanne,
I know of a couple of people whose ALT/AST were in the 5000 range and one who was in the 10000 range...so yes, 30 times is quite possible.
On what result did your doctor "rule out AIH"? You should try to not stress out too much but AIH is a serious illness if left untreated. Luckily, you are on the meds you would need to be on if you are diagnosed with AIH but they'd have to increase your pred till your numbers are stable and normal. I would request a referral to a hepatologist. At this point, I can't imagine anyone ruling out AIH without a biopsy or, at minimum, further antibody tests (which are negative in some AIHers - that's why the biopsy is most important). Your ALT is still too high. What's your bilirubin level?