Rather you would want to use an array of something like the Freescale i.MX535 Quick Start board for $149 to compile optimized ARM packages:
If anyone wanted to buy some of these to help compile Debian packages, I sure wouldn't want to stop them.
But perhaps another option to also consider is this: I wonder if "crowd-sourcing" from the Raspberry Pi community itself (once the first 10,000 units hit the scene) might be feasible to assemble a large-enough, loosely-knit farm of Debian-package-compiling machines.
After all, when the original Debian image for RPi was posted for download, about 35ish download mirrors appeared in about 2 days, without anyone even asking for help (AFAIK). This would suggest that there are many people out there already willing to help Debian in whatever way they can.
This is just idle talk, but perhaps if reliable, easy-to-follow directions, or better yet, a script, were/was assembled and posted (as how to set up Reprepro+rebuildd+sbuild), then it would be easy for volunteers to set up their RPi's to "join the build farm". Perhaps the assembly of such instructions might be a great use of time, while we wait for those first 10,000 units to hit the scene.And perhaps just a few of those Freescale units, in the meantime, might go a long way for someone wanting to do a real trial run of learningReprepro+rebuildd+sbuild, so that the instructions could be verified as working.