I've read that tallit stripes were originally blue and at some point morphed to black. What I'm wondering is if anyone knows any oldsters who can attest to actually seeing this in the frum velt in their younger years, i.e. not in a modern congregation but among yeshiva-leit or chassidim.
Stripes on Tallis states that the Pri Megadim stated that the custom was to use blue in his time (mid to late 1700's). Apparently both customs were extant long before. I saw an article that Yigal Yadin found stripes on taleisim (like today) at Matzada but I lost the reference and do not recall if he mentioned the colors.
Peri Megadim (Eshel Avraham 9:6) writes that the custom was to have blue stripes on the talis, which came to remind one of the techeiles. The custom, however, is to have black stripes on the talis. This is possibly because the ink that the techeiles was made from was black (See Rambam, Tzitzis 2:8 and 2:2). Alternatively, it is so that people won’t think that this is actual techeiles.
Peri Megadim explains that although a talis should be the same color as the strings, the stripes do not constitute a problem, because we follow the principle color of the garment.
This means that nowadays people can wear differently colored stripes without a problem and that the colors do not have significance.
Some sources say that the blue stripes were a reminder of Yosef's coat. Some shul's in Germany had a limited number (I think only 6) of blue striped tallitos. These served as motivation to encourage youngsters to get to shul early.
http://opensiddur.org/wp-content/uploads/2010/11/Tefiloh-Sefas-Yisroel-Open-Siddur-2016-01-13.pdf page 14 (23 of the entire PDF)