Fair enough. Totally get where you're coming from.
Lightroom doesn't have the slightest concept of what Digital ICE is, so the IR channel would be quite pointless in LR. I figured it'd be helpful to you so I pulled up my copy of Vuescan and scanned a blank area as if it was a transparency into a raw DNG file then inspected the meta-data (below). It creates a DNG file with 4 16 bit samples per pixel, one of those samples I'm assuming is the IR channel. Looking at the meta-data, it puts Linear Raw as the photometric interpretation so there's no gamma correction happening to the samples, and the raw samples are ranged from 0 to 65535, so it appears to literally be a raw dump off the scanner driver. It also puts the color matrix for the scanner in (nice touch), and the color balance XY coordinates of the scanner's light source (even nicer). If you look down at the bottom of the list, you'll see that's it's outputting a DNG version 1.1 file, which is literally a lowest common denominator version. Pretty much anything that supports DNG should be able to read this file with no problems, especially given that the current version of the spec is 1.4.
I then pulled the file into LR, and.... it imported it just fine. You don't see the 4th sample and LR just ignores it and behaves as if it's just isn't there, otherwise, it works exactly as I'd expect it to. You can go into the develop module, change the WB, exposure, pretty much do everything that you can do with any other DNG file.
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Adrian,
Thanks for this post. This is important information in favor of Vuescan.
Phil Burton