1. In point of fact, most people DON'T keep "thousands" of photos on their mobile device. A few hundred at best, because they have to keep room available for music, for movies/videos, for apps and so forth.
I know several parents with young children, including myself, that do in fact have large numbers of photos and videos on their iPhones.
2. iPhoto for iOS uses the Photos library and Camera Roll. When I open iPhoto on my iPad, my events and albums (synced from my Mac using iPhoto) are there, which of course makes it a snap to locate the particular photo I want. Maybe you're not using the "albums" and "events" buttons in iPhoto for iOS for some reason?
Now that's intriguing -- I maintain an iPhoto reference library with a directory structure to what I outlined in my initial post, i.e., year, then event. So you're saying the my current iPhoto configuration would be transferred to the iPhoto on the iPad? What about the iPhone?
3. Re-reading your post I'm getting the feeling that you have decided to micro-manage your own folders and images in the Finder rather than using iPhoto to do this. Ironically, iPhoto stores them exactly the way you do, so you're very likely doing a lot of extra work for nothing, making what you want to accomplish unnecessarily complicated.
I don't do a lot of extra work for nothing -- MANY people I've conversed with despise the way iPhoto organizes photos by "event". As I mentioned, I use iPhoto in a reference capacity, and in iPhoto, I have pretty much the same directory structure as my photos on disk. I just create a folder in iPhoto for the year, then drag and drop folders from my iMac into the appropriate year, and an album is created automatically with the iMac's folder name. Simple, and well organized.
You might consider this: on a hard drive with plenty of room, create a new iPhoto library (ask me if you don't know how to do this or can't find it via a search) and just drag photos from your folders completely willy-nilly into iPhoto. You'll find that they will organize themselves by their time stamps into events, and you can create albums that contain pictures from multiple events (and combine or split events as you like).
Now try syncing this experimental library to your iPad instead of the manual one you've created, and I think you'll see that your albums and events will show up in iPhoto for iOS exactly as you and iPhoto have organized it. Given that you've already narrowed photos down a great deal on your own, this should enable you to quickly and visually spot the photo you want to alter/share/print/etc.
