I use a lot of corn in various homebrews, and started playing with rice. Just saying.
As for the IBU's in German Pilsners. data from OCB, page 388, anaylsis by the VLB of hundred tested yearly.
year Min Avg Max IBUs
1973 16, 34, 50
1995 no entry, 30, no entry
2005 no entry, 27, no entry
2008 13, 26, 37
For comparison World Beer Cup 30 to 40 IBUs
BJCP 25 to 45 IBU