Using IR filter on Canon 7D or Canon 450D
Canon use to make a DSLR specifically for astronomical use: the Canon D20a. It dispensed with the sensor IR coating. It may be what you're looking for.
Otherwise all DSLRs will register IR wavelengths albeit at very slow speeds. As long as your imaging a fixed subject or using a very stable tracking platform, you might get away with some good astronomy filters and long exposure times.