Looking for a delay/looper with specific requirements. Help?

I like the TC Flashback x4, but I wish it had the option to change pitch when adjusting the delay speed. And when I adjust the speed while it's repeating, the sound seems to decay quickly - even when feedback and delay levels are up. I would like to keep the feedback going and get weird with it.

Also, the repeats always degrade. I wish it had a mode where the sound doesn't degrade, the high end doesn't roll off, etc.

Is there a delay + loop pedal that can do what I'm asking?