well it was damn near impossible but i got it out..
pulling for about 30 minutes on the housing wire stretched it out enough such that i could wrap it around my hand and yank it out of the top tube
my guess was wrong, there was no inner metal tube, so the only thing left behind was shredded chunks of decayed housing... they were pretty much glued to the inside of the top tube so i used an old spoke to fish them out, not unlike rowan's suggestion... one bit was so stubborn it required a hammer and drift to knock out.. couldn't use a shifter cable because if it had gotten stuck while pulling it would've left no way to push it back out in the other direction
the openings were so swollen i had to work a round file in them for a bit until the new housing would pass through smoothly
thanks