I got my 1.25" spacers last night and put them on along with the 15" Cherokee aluminum rims with Big O M/T tires that I picked up used.
The rear fits just fine, and the front literally just barely fits. There is about 1/16th of an inch space between the caliper and the wheel. I'm thinking the space will increase as the pads wear, so it might be a problem when I need to put new pads on. The tire rubs a bit but not bad.
After thinking it through I've decided that this will not work out in the long run unfortunately. Everything from this point on is going to just be a band aid. The spacers are a band aid because the wheels are too small, fixing the pinch weld and front wheel well section is a band aid needed because of the spacers, and anyhting else I need to do will be a band aid. Plus I would have to pay to get the tire pressure sensors switched over, and since I don't really have the money for that (since then they would need to be rebalanced as well) I would have to wait forever, which would tie up the money I could make by selling the stock wheels.
In all, 15" aluminum wheels WILL NOT FIT!!! Period, end of story. Technically they will, but for all practical purposes they will not. Don't waste your time and money. It's not worth it in the end. Going from 17" wheels to 16" wheels is fine, and steel 15" wheels are probably ok, but 15" aluminum is a no go.
I'll take some pictures to provide proof for those of us that need to see it for ourselves. Now it is no longer just someone saying that they won't fit, I've tried it and proved it doesn't work right. Can we all say "DUH"?

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2005 Jeep Liberty Limited 4x4
BFG A/T KO's
Custom roof rails
http://www.cardomain.com/ride/2935427