Neuro Option 1:
Tandem ring ($32) + a second Lee Holder ($88) + 4"x4" CPL (varies, but $215 seems the good quality price point) = $345
Neuro Option 2:
105mm ring ($64) + 105mm CPL (varies, but $300 seems the good quality price point) = $364
(Takesome1's option of handholding doesn't really fly for longer exposures, so I'm going to pass on that. Thank you, though!)
Now I'm all for hoarding gear for future use, but I use my current ND grad setup once a year. I have the money for the above but cannot reasonably justify it, and I don't see buying it inspiring me to shoot with it much more often.
So, revising Neuro's #1 option above:
Tandem ring ($32) + a second Lee Holder ($88) + renting a 4"x4" CPL ($30 from LR) = $150
And I have a choice to make. Shoot either with an ND Grad or a CPL, or pay $150 to do both simultaneously.
Other ideas? Or are my options about right?