I've got a Pro Multiwave distortion from Source Audio with an unusual configuration: Six presets, in two banks of three.
With an expression pedal, you can morph smoothly and completely between the two banks: 1 turns into 4, 2 into 5, and 3 into 6.
This includes all settings including the programmable 7-band EQ and various modes of OD or multispectral distortion.
Can sweep from semiclean (or just EQ'd) into high gain distortion, or simply from one flavor of OD to another.
It has separate dry and distorted volume controls, so one preset can be set up as entirely dry.
Cool possibilities there, and occasionally some pretty wild sounds halfway between highly disparate types of processing.
Morphing can also be done on some advanced rigs using an expression pedal to change from one set of gain/tone/volume settings to another.
I'm sure most of the modelers must be able to do this.
My old school Triaxis tube preamp can accept a MIDI expression pedal to sweep all the continuously-variable settings between two preset values.
I've never used that capability, but it could be programmed to do what the OP wants.
One limit is, you can't sweep from one preamp to a completely different circuit configuration: only the parameter settings themselves will morph.
To go from one preamp mode to a different one, you'd still need to use program change, not just MIDI pedal or other CC remote control.
That's because in Triaxis, some sections of the circuit rearrange themselves like building blocks for different preamps.
But there's a lot of range in some of those preamp circuits.
The Mk IIC+, Blackface, and Recto modes all can do both great cleans and drive tones.