Regarding that earlier post I made - confirmed this is due to missing modules. These modules are included in the original h-e-n hostmode kernel (that's how there are a few videos out there showing the N900 play DVD's etc) but they are not included in kernel-power.
The bad news: You cannot transfer the modules from the old hostmode kernel to kernel-power because of symbol differences.
If you try compiling them against kernel-power-headers you will be able to get cdrom.ko and sg.ko to load but not sr_mod.ko, which means that it's as good as nothing.

Only solutions to that problem:
1. Revert back to the original hostmode kernel (and lose all the other unrelated improvements that kernel-power features).
2. Recompile kernel-power and add support for necessary modules (such as CD-ROM). I've written a very thorough guide on how to do that.
3. Since I've already done method 2, I now have a kernel image based on kernel-power 46 with support for CD-ROM drives and DVB dongles. I may upload it and post a download link once I've tested it and am more-or-less confident there are no problems or regressions. If you want it earlier, please send me a PM.