I do agree with erik krause that it is possible to get a whole RAW
file into a 16-bit tiff (although what you do with it afterwards to
make it look nice can be tricky).
however you can't always fit the whole dynamic range of course into a
raw file. who else averages bracketed images into one 16-bit tiff to
achieve this? it seems to work quite nicely (though again, tweaking
this "flat" image to look nice requires some tricks)
furthermore, it seems that tonemapping one of these single averaged
16-bit tiffs, seems to give the same result as 3 bracketed panoramas,
fed into the tonemapping.... can anyone else confirm this? it could be
a solution for those who want to tonemap panoramas but don't want to
stitch 3 times more.