Sure there is a strong low pass-elimination filter build in front of the sensor, but if you expose long enough, nevertheless it's possible to do IR wit the newer Canon models. But it's also possible to run into problems cause of the long exp.. If there are windy conditions, the chance to get a blurred image (trees, branches etc.) is very high. I'll try to get an old 300D or maybe a Nikon D70, because it's cutoff filter was way more weak and with the 300D/D70 you can achive exposure times between 1-20 seconds. This will dramatically advance the chance to get a sharp image without any motion blur.