I've been slowly combing through various subsystems on my RX and the most recent system to get some love was the PCV system. I found that every hose is still available, except the one that attaches directly to the PCV valve on the intake manifold.
I ran down to my local auto parts store with the original hose in hand to pick through their selection of hoses. WELL! It turns out that the small heater hose from a 2002-2009 Ford Explorer (Dayco P/N 87730) is almost a perfect fit. Hose was about $7 and needed to have a small portion trimmed off.
NOTE: EPDM is NOT oil safe, so until I find a better solution, I'll need to keep an eye on this hose to make sure it isn't perishing too quickly.