Now that the "Recently Active Threads" page is coming into more prominent use among dedicated monks, you might try a strategy of posting a reply to your own SoPW thread when it hasn't gotten a response from anyone else.

If the OP problem is still unsolved, use your reply to provide some additional information -- things you tried that didn't work, a rephrasing of the problem, some extra detail, etc. This will cause the thread to stand out on the Recently Active page, and also improve the likelihood that others will be able to help. (If you did find a solution, post that -- you'll get more XP!)

Would it be possible to create a Monestary section where such really deep or obscure questions could be stashed...

I wouldn't trust most SoPW posters to sort out their issues in any reliable way according to "really deep or obscure" vs. "not really deep or obscure".

You have the ability to control the content of your own home node at PerlMonks, and you can create a standard "signature" that is automatically appended to all your posts. How about adding a table to your home node that lists links to all the SoPW nodes you've posted that are still unsolved, then make up a sig that says something like "Want to answer some HARD questions? Go to my home node!", or words to that effect.

(I keep a list of favorite code I've posted at PM on my home node, mostly so I can find it later; modesty and common sense prevent me from referring to that in a sig. ;-)