The 6" Cold Steel Hold Out I is 0.7 oz over your limit. Perhaps you would consider that acceptable for an extra 1.5" of blade length over your target? If you ground it down to 4.5", I'll bet it would be under 7 oz.
Going the other direction, if you are willing to go down to a 4" blade in exchange for super light weight and exceptional IWB carry-ability, the AL Mar Eagle Ultralight only weights 2 oz.
Frankly, the vast majority of good designs in the type you are looking for are either right at the 4" mark or up at 5.5". In asking for 4.5"+ under 7 ounces, you are limiting yourself in such a way as to exclude the best designs.