Here's what I was able to find:

http://www.gitabike.com/cgi-bin/shop...Uao&0_option=1

This is pretty much their standard steel geo.

FWIW, the info that Merckx provides about their frames is minimal compared to other companies. Their seat tube measurement is center to center (add 1.5cm for center to top). To get an idea of the standover on a 63cm Merckx, just take the standover number for your current 60cm bike, and add either 3cm (if you're measuring center to center) or 4.5cm (if you're measuring center to top). Standover on the Merckx may well be a little less than that, thanks to the slack seat angle and low bb, but not by a significant amount.

Oh, and if you are indeed "big and fat" as your sig says, you might prefer a Merckx MX Leader (made of Columbus Max tubing) as it's a good bit stiffer than the round-tubed bikes (Corsa, Corsa Extra, Century, Professional, Strada).

SP
Bend, OR