Given Hardy's struggles as of late I think his value is greatly diminished. Erik Bedard is way too much wishful thinking in my opinion. over the past month Hardy has hit .239/12/3/7/0. If you think he'll get back to earlier season form (I personally don't), then consider moving Guillen who would have more value in a trade. If Hardy cleared waivers in your league then you know demand isn't especially high for him and often managers are reluctant to give up for a guy who was just a free agent regardless of how good he is (this makes little sense to me, but is always the case). I think for Hardy you'd get a solid #3 pitcher like Ted Lilly, Mussina, Capuano, Gil Meche (good ratios, not many wins), Kenny Rogers. Hitters just depends on what position but try for an undervalued guy like Casey Kotchman, Eric Byrnes, Dan Uggla, Curtis Granderson, etc. I don't think you'll find anyone who thinks Hardy ends the season on his 35 HR and nearly 100 RBI pace. Best of luck with your trade.
Recent 1 for 1 deals with Hardy on Yahoo:
Hardy for Rich Harden
Hardy for Victorino
Hardy for Billy Wagner (never happen in most leagues)
Hardy for Jeremy Guthrie (this would be good for you and possible)