The very best beekeeping tool I've ever owned has been a good quality, pocket-sized camera that has great macro focusing and processing capabilities. I use a Sony DSC-WX80 which I have had for years.
These are the questions that will immediately come to your mind:
Q: How do you manipulate the camera when you're wearing those thick beekeeping gloves?
A: I don't use gloves like that. I use extra-large, extra-long, blue nitrile gloves like they use in hospitals. I love the dexterity they provide and the bees can't quite get their stingers poked through them... usually. Haha!
Q: Doesn't the camera get propolis and nectar and honey on it?
A: Of course. But, a wet wipe like they sell at Wal*Mart, for example, easily removes it.
So, why do I think a camera like this is so valuable? Because:
1) I don't care who you are, it is often really difficult to see eggs and very young larvae in the field and through a veil. As you know, just seeing the queen doesn't prove that she's productive.
2) I am a low-invasive, low-interventive, bee-centered beekeeper, and a camera like this actually helps me to disrupt the colony as little as possible by letting me evaluate what's in the hive afterwards.
For example, I visited a hive today that didn't seem as active and vigorous as I would have liked to have seen from just viewing the activity at the hive entrance. Were they queen-less? If they had a queen, had she failed as an egg layer?
I opened the hive, and in this particular case, I spotted the queen right away. I took several quick photos of her, and the area of the frame immediately surrounding her. Later, back at my computer, I was able to study the photos and easily saw that there were young larvae in the cells surrounding her:
As a bonus, I could see a newly emerged worker just down and to the right of her abdomen: