2004 Honda Accord Honda Shakes

I have a 2004 Honda Accrord with 73,000 miles on. I have now spent a little over $500 trying to get this issue resolved. When accelerating and mph hit 40 the car starts to shake a little and at 45mph it stops. But when I get back up to 60mph it starts to REALLY shake but only when my foot is on the gas and anywhere from 60-65mph. If I go over or slow down it will stop again. I have been to a number of car shops and they cant seem to find out what is causing the problem. They all tell me I need my tires balanced. I have now had all tires balanced a few times. I have rotated tires. I have replaced all four tires with brand new tires. I have also had two wheel alignments because each shop says maybe they didn't do it right and thats still whats causin the problem. Another shop said I had a bent rim.I have replaced the rim and it reduce the shaking a tiny bit when I am around 40mph but definitely didn't do anything at 60ph. I am in desperate need of help. So can please give me a sugestion. PLEASE!