Hmm... I've had the white screen thing on occasion myself but I had a feeling I'd had it with the original kernel, perhaps I was wrong. I take it it's the first time for you? I haven't got anything bigger than a 4Gb card though I'm using two of them and it seems to be working just fine at the moment. I'm using 94% of one card and 37% of the other and no ill effects at all that I can report.

I can't comment on the bluetooth as I don't have a mobile phone. My bluetooth keyboard however's working fine but I guess that's a little different to pairing with a mobile.

I'm new to the MMC stuff so I don't really know what I'm talking about... but, the patch I've applied is one that's for the kernel head and subsequently there's been quite a few changes in between the N800's 2.6.18 kernel and where the head's at currently including, I believe, significant speed increases. It looks like the SDHC patch has been accepted for the 2.6.21 kernel. Hopefully someone that does know what they're talking about will be able to do a more thorough job than I and fill in the gaps.