The iRex is definitely too rich for me, but I'm not sure its abnormally expensive since it is the only one that does all that stuff [grin].
There are some folks that think its a definite winner. You can visit the thread:
and see/ask questions of an owner.
If it doesn't meet your needs, I would suggest you really only have two other alternatives at this point. 1) Look for a tablet pc, or 2) Wait for the market to evolve.
I do not have experience with iRex and folks that do seem to love them. However, I wouldn't be surprised to find out that the state of eInk today does not support seamless annotation capability. I think you will have to buy a tablet, or wait for newer screen technology, such as pixel qi.