Sigma have a DSLR with a removable IR filter that is used to prevent dust on the sensor. Doesn't help us in astrophotography to keep sensor clean but unlike other cameras there is no need to modify i.e. rip your camera apart. I saw and held one today ... bit heavy ... bit pricey ... but very nice piece of gear with 14 megapixel Fovean chip.
http://www.digitalcamerawarehouse.co...egory150_1.htm
