There are several threadless bottom brackets that would work with your frame. However, if I've read your posts correctly, you do not want to change cranks. If so, that will be problem. I'm only aware of one threadless bottom bracket that is not a cartridge type with sealed bearings and a captive, cotterless spindle. Even then, there is a very good chance that it won't work with your existing cottered spindle. You're almost certainly going to have to get a new crank.