making an expression pedal controlled mixer, and bypass looping

[spectraljulian]

So I'm trying to figure out what to put together for my next DIY parts order.  My next project was going to be a power supply for my board, but I decided that can wait. 

There are a few things I feel that could make my board way more convenient, and I'm going to put together an order or two pretty soon to get all the stuff to make these things:

1. A TB/Feedback looper for my modulation.  Also, I might add a switch to allow it to change from one position in my effects chain to another.   
2. A loop selector for a clean loop and a fuzz loop, with the ability to stack the two loops in series if I wish, in either order
3. A box to plug my Stereo Memory Man with Hazarai into so that I can get trails, so I can fade loops in and out, and so I can use advantage of its stereo capabilities in mono (record separate loops into the left and right channels, then pan between them, also I might add a switch or two to allow myself to chain Left into Right)

So the main point of this thread is that in number 3 I want to have an expression pedal control. 

Ideally I'd like to be able to switch between two expression modes: L/R return BLEND and WET VOLUME
1.  L/R blend going from 100% L/0% Right, 100% Left/100% Right, and then 0% Left/100% Right.  100% being unity volume, 0% being silence.
2.  Control the overall volume of the L/R blend at whatever that was set at at before the expression mode switch was hit

I think the 2nd best option would be just to have a BLEND expression control and have a switch that mutes left, right, or neither.  Then to fade out a loop I'd just have to hard pan one way, throw the switch the other way, then pan back when I want to fade. 

Also, I could have 50% 50% be the middle instead of 100%/100% if it makes it a less complicated build.

Compatibility with expression pedals is important to me as well.  So I'm thinking a CV/ optoisolater solution might be best, although I've never done anything with optoisolaters.

For the mixer portion, I'm planning on basing it off of the GGG mini mixer.  I'm not exactly sure how to attack my expression pedal needs.  So any advice in that department are very welcome.  I'm thinking

Here are my crude paint drawings of what I'm planning on:

(any advice on what size hammond boxes to order or any other advice would be great  )
1.
My Mixer/looper for my memory man:


2.  My fuzz/clean loop selector switch diagram


3.  Location switch for my feedback looper (I'm gonna use http://www.beavisaudio.com/techpages/PedalHacker/LooperWithFeedbackLoop.gif for TB looper/feedbacker design)
-I'll have the locations be in between my Memory Man and its mixer (for the effect of an FX loop in my delay) and the normal place where I put my modulation. 

[Processaurus]

Might help:

http://www.national.com/mpf/LM/LM1036.html

[spectraljulian]

Hmmm, that looks like an interesting possibility.  It can do exactly what I want I believe.

If I used that and and I had a switch to switch from my CV pedal controlling blend to controlling overall volume, I'd want the voltage being placed on the balance control to remain the same.