Just wanted to correct a little misinformation about Excell tubing and its purported use for only small frames. I briefly owned a Haral CSK built with Excell tubing - one of their conventional frames, as opposed to the more familiar "funny bikes" they built in the later '80s and '90s. It was a 60cm, and even back then I wasn't a small guy - I go about 185 lbs. in "racing shape." It was red cromovelato, bought on the cheap because the candy clearcoat was badly scratched from lying around the shop. Sweet ride, much like 753. I thrashed it for three winters and sold it for more than I paid for it - it's one of the few non-custom bikes that I wish I still owned, as it fit me to a "T". At any rate, I had no problems with its stiffness, and it certainly didn't fail, so clearly either their formulation or the additional heat treating made the tubing plenty strong.
I believe Brent Steelman built with Excell for many years, and there were several models of Giordana-branded frames imported by Gita in the '90s which were built with Excell - Podium was the specific tubing, IIRC. Don't know who made them, but they were decent, and I never saw a failure there either.