Has anyone made a mod that allows you the option of using different types of explosives to open locks in the game? If not, here's an idea for one.

Success would vary based on the quality of the explosive, Explosives skill, and failures would result of the items within the container being destroyed and/or damaged. You use a dynamite to open a container? High chance of failure. You use shaped C4 around the locking mechanism? High chance of success.

Edit: Also, is there a mod that removes the arbitrary number requirement for lockpicking and just makes it progressively more difficult the lower your skill level is?

Done, done, and done. Mods for Fallout 3 original have all these features and more for years. Try Fallout 3 Wanderer's edition. EXACTLY like you are describing almost. Stronger explosives are more likely to open the lock, items can be destroyed, and you can also try lockpicking below your skill level but the chance of failure rises dramatically.

http://www.fallout3nexus.com/downloads/file.php?id=2917 is the mod you're referring to (it has also been incorporated into Wanderer's edition and a few other mods) and I've been considering remaking it for NV. I'm glad to see people have been enjoying it in its various forms. Great encouragement for me to keep modding.

I'll probably port it over to New Vegas eventually, but I'm a bit busy this week. If someone wants to port it over to New Vegas just email me beforehand so I can make sure you know what you're doing.