A pink Joe Waugh - first build ever

Bar end shifters would be very tempting if I could find them for a reasonable price. I now have index-compatible gear cable so I could go indexed if I wanted to.

What would I have to take into consideration? I would probably get a 6 or 7 speed block, so would I then have to get a Campagnolo 6/7 speed bar-end shifters? Are they always indexed shifters? What diameter do your bars have to be to fit them?

You'll need an indexed rear derailleur (unless you get lucky). I'd stick with friction shifters, seeing as you've already got most of it. Suntour bar ends are good, they use a ratchet. Have you considered stem mounted shifters like this.