Try these:
www.clicksor.com (Textlinks, Popunders, Layer Ads, Search Boxes, ...)
www.etology (Textlinks, Banners)
www.eonpal.com (Textlinks, Banners, Search Boxes)
www.avnads.com (Textlinks)
Never had any bad experience with these
The 1st and the 3rd are probably the most interesting to you, as you want search boxes/results.