I have found two lead foil replacements.... 1) The foil from around the neck of a wine bottle. It is a little bit stiff but fairly durable. 2) The aluminum(?) foil material used to make tubes for toothpaste, ointments and that which alot of you have... OIL PAINT!!! This foil is very malleable and strong and of a decent thickness for 54 and 75 mm work. For larger scales you may want to fold it over once or twice. I am lucky enough to get these tubes empty from the hospital where I work before they fill them with guck but it doesn't take much to slit the used tubes open and clean them out... Reuse- Recycle
Hope this is useful to someone
Colin