Schwinn makes a SS bike with a coaster brake made from steel and a bit more expensive one made of alloy. I use a steel one with a nitto moustache bar and a brooks b-17 seat for my everyday commuter. It is heavy but im pretty sure it would stand up to a big person, im 5'9 and 190. Steel SS runs about 200 bucks, alloy 250. I was lucky enough mine is an older model and it is black. I like black. BTW, if you do buy one of the schwinns see if the dealer can hook u up on a seat, different tires, and a different handlebar-- a real seat/ flat mountain bike bar, and 1.75 and bigger mtn bike tires will change the whole bike for the better. Unless of course you like to ride completely upright. OK im rambling on, obviously time to goto bed.
http://www.schwinnbike.com/products/...ail.php?id=259
http://www.schwinnbike.com/products/...ail.php?id=251
Another good option would be to find a Van Dessel Straight up, 21 pound aluminum cb bike-- they are always out of stock but u seem em on ebay from time to time. Van dessel's web page is down maybe they are finally getting off their ass and making some more bikes.
"The expanded 2005 product line includes road, time trial / triathlon, cyclocross, XC mountain bike, and city bike models as well as the updated Country Road Bob.
The new website with complete details will be up very shortly!"