Saw this and thought these might help.
I'm in the KC area, I'm not a powerlifter but have looked around for something like that in the past. Here is an old thread with some info in it.
Look at usawa, hawkcapt1912, and KCBen's posts. Might get some leads there. I'm sure none of these are in Olathe and will be on the Missouri side.
Another option is 68's Inside Sports in OP. - 9111 Flint Overland Park, KS. Will Shields, a former Chiefs player owns it and seems to be fairly friendly to "noise makers". 3 racks, DB's to 120. Paul Carter (don't know if that means anything to you or not) has be in there a few times when I've been in and makes quite a bit of noise. I frequently use chalk and have never been asked not to.
Hope that helps, good luck!
Edit: Sorry, didn't post link to thread.