Sorry for not answering your actual question, but the Philips bulb seems to be still widely available (in Netherlands at least). Why not stock up?

http://shop.fotohuisrovo.nl/product_...fd3588652eefe1

http://www.diaprojectie.nl/product.a...0-%2075%20watt

http://www.hafonline.nl/index.php?pa...mart&Itemid=30