If you really want more bass, it is probably either a speaker issue or a "desire" issue. The revel's are very very flat speakers. They are only giving you what is in the signal and the amps you have tested are all very good amps that are pretty flat. You may want to get an EQ and boost the low frequencies.
Another option, if you like the sound of the revel upper end is to try a pair of Infinity P363. Those speakers have a pyscho-acoustic boost in the low end that many people prefer, and have a similar sound to the revels above that.
I know it is heresy what I am saying on a high-end forum, but "good" preferred sound doesn't always come expensive to everyone. And it worst it is only a few hundred $'s which is probably less than you've lost on your amps.
Another option, if you like the sound of the revel upper end is to try a pair of Infinity P363. Those speakers have a pyscho-acoustic boost in the low end that many people prefer, and have a similar sound to the revels above that.
I know it is heresy what I am saying on a high-end forum, but "good" preferred sound doesn't always come expensive to everyone. And it worst it is only a few hundred $'s which is probably less than you've lost on your amps.