I think I found the answer!
(lease let me know if it's not the right place to put it)
I had the same problem where I would download and sync a whole pile of podcasts in itunes, sync using itunes, get all my favourite podcasts ready for my commute, then leave the house only to find that they were unavailable.
After reading the above I tried something that should fix the problem. here's what I did:
1. uninstall the app
2. reinstall the app
3. download and sync podcasts using itunes and phone cable
4. open the fresh install of app
5. selected "don't sync..." from the inital alert box.
6. double checked podcast app settings to make sure that sync was off, it only kept new podcast, and there was no auto downloading or checking
7. checked to see if podcasts were all there and new (they were)
8. turned off wi-fi and checked again to make sure the stupid cloud wasn't there (it wasn't)
9. crossed my fingers that when I leave the house next I could listen to my favourite shows
Hope this works for you guys!
Good luck.