I'm running this bike with thumbies. I have installed a downtube cable stop just above the nub on the downtupe that was meant to keep the shifters from sliding down. There's an integrated cable stop about three inches above the bottom bracket on the downtube. There is not a guide at bottom bracket on the left side, but there is an integrated one on the right. My front derailleur is constructed without a cable stop. I want the cables to be proper on this bike, but I want to know what my options are.

Is there such a thing as a seat tube stop?
Can I simply insert a length of cable housing in the downtube stop without it working itself out and setting the shift cable up to self-descturct by rubbing on the stop?
Are there FD options (period correct or otherwise - but not completely dorky looking) that have an integrated stop -like a SImplex Prestige) that can handle a triple?

Thanks in advance.

Not an April Fool's thread, honest.