Modular Synth Panels

I plan to build the JH Varislope Filter in July and have been putting  
together a few modifications as well as trying to figure out a panel.  
This filter can eat up a lot of panel space, especially with the  
onboard morphing LFO, thus I'm leaning towards small knobs in the  
hopes of getting everything to fit into 3U. I've posted a few examples  
to get some feedback from the group.

The first layout uses 3 switches to select all-pass/low-pass for the 6  
filter stages (as JH did with his prototype):

http://www.tellun.com/varislope_panel_1.gif

The second layout uses 6 switches, which makes things quite tight, and  
I had to move the AUX input jack (for the LFO) off the grid:

http://www.tellun.com/varislope_panel_2.gif

The Clean/Dirty switch is marked "C/D".

Both layouts are still quite dense and I had a tough time figuring out  
where to put the switches. The pot and jack spacing is similar to the  
spacing on my JH Scanner panel so I know the pots and jacks aren't too  
close. But the 3 switches in the centre of the panel may make  
accessing the nearby pots a bit cumbersome. I'll have to cut some  
plastic and try it out.

I want this filter to have a similar interface to the standard MOTM  
filters (3 audio inputs, one audio output, 2 FM inputs [one with a  
reversing attenuator]) and have the following modifications planned:

1. Add a summing amp to support 3 inputs with 100K log pots (for 100K  
input impedance).
2. Add an inverter to the MOD1 input so that the FM1 pot is a  
reversing attenuator.
3. Skip the MOD3 input (3 external mod inputs is more than I need,  
especially with the built-in LFO).
4. Add a driver to the LFO output that will support a bicolour LED  
(like MOTM-320).
5. Skip the bypass switch, I've never needed one on a filter.
6. Skip the output pot, I've never needed one on a filter.
7. Change the output driver so that the Mix/Filter switch is not  
required to completely silence the Dry signal from the output.

These modifications require 4 op-amps. It'll fit nicely onto a MUUB-4  
board, spookily enough.