Quite happily, I stumbled upon this thread and easily implemented the ProductFilter2 mod, however...
I'm hoping someone has discovered a work around for this but yet again, I've run into the filter by price problem I always have with additions like this one.
I have several products that are priced by attributes and unfortunately, this mod doesn't, and may not be able to, take that into account.
http://minu.me/304v
Now choose filter by Price Low to High.

The first two items are seen by PF2 as $0.00 priced because they are priced by their carat sizes.

I've also tried the product_filter_by_attribute_and_price_range_0-7 mod with no luck because it wouldn't filter by a price based attribute.