I have read several posts on how people have inserted different types of nails and rods into the end of a wood shaft for extra weight.  Has anyone tried to replace part or all of the taper with some type of steel?  I thought about getting some of those broadhead adapters and filing the threaded part down smaller and smooth and using epoxy to attach it with a hole in the end of the shaft.  Maybe that wouldn't be strong enough.  Maybe it could be a smaller steel cone that would only take up half of the taper and still have some sort of post to glue into the shaft (maybe even small threads?). If it worked it seems like it would add a lot more weight than people were getting with just a nail or small rod.

Pack, I was gonna try footing an 11/32 shaft with a 23/64 oversleeve of aluminum arrow shaft, with a screw-in adapter...that way you could play around with tip weight, plus it should strengthen the shaft somewhat...at least that's my theory....

Yes fatman that works.... I did that to fix some broken arrows... it added some weight & lowered the spine some too.... I used 2317's cut to about 2-3".....

I've had the same issue with wanting to weight up a POC shaft.  I spoke with Mike at the Nocking Point and he suggesting soaking in Watco Danish oil.  He did a set for me and it worked great.  I just finished a set that I soaked for a week in Watco Teak oil.  29in. finished shaft with 125gr. point comes out to 600gr.  Just soak them for a week and then let them dry for another week before finishing.  they should be completely waterproof when done.

The aluminum footing has a lot of promise for weight and especially FOC. I recently had Raptor Archery taper and foot some ACME POC, Ted left the Osage footing extra long-5" BOP instead of the usual 2" so the total weight with a 160 BH is 650 grains-for a 29" shaft. There is quite a bit more weight up front; but it still is not 'extreme' FOC.