Summing amp build

I've done a healthy amount of research on the metas and online for this specific project but so far havn't found exactly what I'm looking for so I thought I'd see if anyone here had any advice.

I picked up a yamaha pm1000 recently with the intention of turning it into an 8x2 mixing console. I'm really happy with the way it sounds but I have a feeling the Buss channels could be improved or replaced. I havn't had any luck finding a summing amp kit anywhere so I'm planning on building it from scratch and was wondering if any one here has any experience with this type of project?

Would something like this do the trick?

http://forsselltech.com/downloads/schematics/Summing%20Buss2.pdf   

I have a 44 and 48v rail to work with so I'll need to figure that one out too since I think the 992/3's run on 12-24v.

Thanks!

I built a version of Fred's summing mixer pretty recently... very nice results, I'd recommend it.  

Radiance built a very nice version, that I based mine upon.... you'll pick up a lot of tips in his thread:
http://www.groupdiy.com/index.php?topic=27992.0

Also, I'd recommend reading Fred's paper on it, if you wanna understand how the damn things work, as well as
getting a correct value for your bus resistors etc.
http://forsselltech.com/downloads/design_discussions/summing_buss.pdf

I'm using Fred's 993's in mine.... fantastic opamps... he recommended it over the 992 in this application due to
the 992's mid-range bump....
and voltage-wise, you're looking at 24v... I'm using 18v is some places (line drivers and my inputs)
but if you stick with Fred's schemo, you should be good with 24

cheers,
dave