Hi Wilfred Laurier.
I measured it at about 55-56cm. I'm just under 5.8. When standing over the bike, there's barely any clearance but i can still lay my feet flat on the ground. If the frame were 1 cm smaller, i'd feel better about it but i still feel safe with the limited clearance.
In addition to eventually posting some pics on the fitting forum, i'll stop by the LBS to see if a change in stem and/or handlebars will make any difference. I personally don't mind the dent and can fix up the rust cheap and ugly, so it might be more worthwhile to save this bike for me rather than selling it.