All these posts made me think about a few things. The idea of debernardis to use the android kernel sounds the most appealing. The first thing we have to think about here is ROI, return on investment.
I strongly believe that we have to choose a new hardware instead of supporting a bunch of devices so that forces are not scattered. I even think the division of forces between N900, N9/50 and whatever hardware we may choose to go forward with (cordiaTAB or any commercial device that ships with something else) is still a significant fragmentation threatening the effort. Then there is time. We should have a 'beta' release sooner than later. If we pick up let's say the new pre and it takes us two years to finally be able to run our software (say cordia hd) on it in an everyday usable state, it's already too late. We have to pick up a new device now, that our N900 still have a year of life, and in that year to be able to switch.
CordiaTAB may be the thing but I think that most of N900 users want a device with phone function. Phones are more adorable, more personal. If in a year from now I have a cordiaTAB and a galaxy, it will be too tempting to put my little extra time to developing for the cordia which will sit at home than for the phone I have always with me.

A longshot would be to approach one of the smaller smartphone manufacturers, preferably one who has declared interest in MeeGo and urge them to provide us with the blobs we need (for one particular, already marketed device) so we don't waste our time trying to get the hardware play. The selling point will be that the sales of the aforementioned device will boost a little (maybe significantly) and that in two years' time they will have an alternative to android without much development costs.

A final wild idea is to create a new pcb for the N900. The casing, lcd, digitizer etc are sold cheaply in ebay from chinese manufacturers. How much would it cost if we contracted a batch of pcb's with the same hardware (so that current drivers still function) as a N900 but with more ram?