i did chop my lidl sim into a microsim, worked fine in the ipad2, just be sure to change the APN... actually come to think of it you can put whaever you want in APN and it still seems to work for some reason....
be careful when you head home thou, the SIM has roaming active and seems to gobble 80cents or so sending some sort of SMS back home to germany gobbling up some of your credit
even if you do have to buy 20euro voucher, use 15 on data, stick the SIM in a phone and make phone calls with the remaining 5euro