Could these be T-Mobile's iPhone 3G rate plans? I couldn't find them posted yet on T-Mobile's site (and my German is nicht gooden anyway), but reader Germany iPhone User sent us a tip on the image below, so if this is them, then this is them!
Update: Turns out not so much (see comments below).
According to the image, plans come in small, medium, large, and extra large (XL) sizes, from €29 through €89, with 50 to 1000 minutes, free weekends, 0 to 500 SMS, with 500mb of data on the lowest plans, and unlimited on all the rest. Likewise das cheapen plan will get you an iPhone 3G 8GB for €169 (or 16GB for €249) while einen XL will get you the 8GB free! (16GB for €99)