Is there a 43 to 49mm step-up ring available? Any idea which shops have it and how much it costs? Me tried asking in some of the camera shops today but they all said they don't have such a thing.
If you are using the step-up ring for filters, you might want to consider going the 52mm route instead of 49mm. 43->49mm step-up rings are quite hard to find here, but 43->52mm is more commonly available. 43mm thread accessories are woefully few in number, possibly because it seems that the only people who still want these things nowadays are Olympus digicam owners.
you could try FotoGuide. It should cost ~$6. If you can't find a one-step ring, you could get 2, a step-up to 52mm and a step-down to 49mm. MS Color sells a thin 43-52mm step-up for ~$9.
activex, you may want to check Fotoguide as mpenza suggested. However, if you intend to try the step-up then step-down route, remember to check if this combination causes vignetting.