I have an interest in natural history video work using infrared illumination. Most of the work that I have done so far is with cheap monochrome surveillance cameras. They work because they usually do not have infrared cut filters and if you position your lights carefully they give surprisingly good results for such cheap cameras. Even so they are difficult to use as they do not have recorders built in.

I notice that Canon are introducing two new cameras, the XA 10 and the XF 100, both of which will have infrared cut filters that can be removed with the click of a button. However I have not been able to find out whether you can still use the aperture, shutter speed and gain controls without the filter in place.

In the past it was usual for the camera manufacturer to switch the aperture, shutter speed and gain to their maximum values when the filter was not being used. This was to stop users using the camera in full sunlight, the reason being that infrared passes through some clothing fabrics with the chance of revealing what is underneath. Not only did this ruin daylight recording but it was very limiting for night work also.

Does any one know whether the XA 10 and/or the XF 100 permit full camera control without the infrared cut filter?

The XF 100 manual indicates that there is very little that can be controlled in Infrared mode. That is a pity.

With most cameras offering some level of IR imaging, manual control is very limited. One workaround is to have a camera modified for IR only. Obviously you wouldn'd want to convert an expensive system to IR onlly, however I know that there are a number of Sony Nex 5 users that have converted their cameras to IR with some stunning results.
The benefits are multiple; the Nex 5 shoots 1080i video of surprising quality, and it's a relatively inexpensive camera...cheap enough to justify converting to strictly IR. You retain manual control for stills, and also some level of control for video as well. It is using an APS-C sensor, so it is a pretty good performer, and very small. it does have built in stero mics. and you can add an optional mic to the camera.
DPreview has a sony Nex forum, and there are a number of the people that hang out there that shoot strictly IR with the camera. You may want to have a look there