No. If the hitch is only rated to carry 500 lbs, then it's only rated to carry 500 lbs.
Of course, you can probably get away with it, but how many times do you want to risk bending/breaking the hitch, or the connection to the truck?
Backing a trailer with a longer-wheelbase vehicle is difficult. But it's gets easier each time.
thebrakeman ('70), DW ('71), DD ('99), DD ('01), DD ('05)
2004 Surveyor SV261T (UltraLite Bunkhouse Hybrid)
2006 Mercury Mountaineer V8 AWD Premier
Equal-i-zer WDH (10k), Prodigy Brake Controller