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This process has been posted before and unfortunately the critical ingredient of calcium hypophosphite is on the DEA's List I of controlled substances
Bugger. Yes it seems that the calcium hypophosphite is used to make copper hypophosphite as the active ingredient, so no real way around it.
It did get me thinking though about copper sulphate, and if maybe the simple ascorbic acid precipitation of copper from it could be used to make a copper based ink which would be thin enough to flow through holes and thick enough to just stick enough to the sides, then bake it off. This video is about making a gum arabic carried copper ink by that method... http://www.youtube.com/watch?v=9iyRUBvd260
FWIW, the instructable with regards to the calcium hypophosphite is here
http://www.instructables.com/id/Inexpensive-method-of-industrial-level-quality-PCB/step1/Preparing-activator-solution/
And I see using Copper Hypophosphite for activation has also been discussed on DP
http://dangerousprototypes.com/2013/05/15/low-cost-pcb-through-hole-plating/