The problem with maintaining two sensors, one in passive for humidity and one aspirated for temp, is that there isn't a Davis console (I'm aware of) that can feed temperature and humidity on separate IDs (what some folks call "channels"). You could add a 2nd console to receive the 2nd SIM signal, but that doesn't solve how you feed your weather software both consoles' data simultaneously. While it may be possible to run two different, incompatible weather apps concurrently and somehow feed humidity from one and temperature from the other to your website (custom job but do-able), I can't see how you would be able to send both to the same statistics database, let alone online services like CWOP & WU, without some serious custom programming.
At this point, I'd have to side with jerryg. Does it make sense to spend hundreds in initial and ongoing expenses and invite untold headaches all in an effort to save a $45 sensor from annual or semi-annual replacement?
Food for thot. Old Teleman provided a link several pages ago in this thread to an academic study which concluded that naturally aspirated humidity readings are, in fact, less accurate, on the whole, than fan aspirated readings. Why? Same reason as with temp readings: on low wind days an artificial environment can build up within the shield. I remember reading that elsewhere too.
If the cap solution work out, then maybe we can have our cake and eat it too?