Guys, this is the first "permanent" fix that I've found.
[HOW TO] Fix the "Low on space" problem (in plain English) - xda-developers
the actual MOD the above thread is referring to was listed twice, here.
[MOD] Ext4 4 ALL! Gingerbread AOSP + GingerSense Update: 10/27 Normal dalvik fixed - xda-developers
Just follow the first link's directions.
YES, you will have to root, and it might be scary and a pain, but I read up on it for a week, really learning about it, and then I rooted. VERY SCARY, at first, but my friend helped me out. An important thing to note is that the actual process of rooting a phone contains risk, of course, but actually bricking your phone, when done right, contains very little risk. usually the risks come when you are flashing a mod that messes with your radios, etc.
the Mod above does this. your /data/data partition is usually 150mb, max. what this MOD does is move the /data/data partition into the 750mb of internal storage! so it's HUGE now. i have 171mb of available space now, and i can move more apps to sd to make even more room.
i used to just clear my facebook, google+, and dialer storage (text message) data, and my phone would be fine. however, recently, i could not get the low storage warning to go away.
i don't think that verizon is ever going to fix the problem. they have moved on to working on other newer phones. i don't think that htc will ever fix this problem, either. for the same reasons.
that is why i finally decided to root. it's NOT FOR EVERYBODY, keep in mind. for many of you, just doing a factory reset will be a better short-term solution.
but, if you are interested, check out those 2 threads that i mentioned.