Limited Liability is just that, there's a lot of protection covered in it. Plus, a company investing in another company isn't any different than a person investing in another company, so "Bob Productions, LLC" investing/owning/producing "Bob's Movie, LLC" is just as protected as Bob himself is producing "Bob's Movie, LLC", the logo doesn't matter.
The reason I say keep it short is because of the medium it's going to be aired the most on, in this case, YouTube where people won't sit through 15 seconds of logo to see someone get kicked in the groin. Putting a long logo at the end is fine, people have already seen and hopefully committed to the product, or short that you have posted. Even TV sticks to the short logo rule. Granted, airtime is expensive but they don't want to lose viewers to people changing the channel when a prod co logo comes up. Some TV ones are even a half second flash, and that's it. Openings are the same way, where a show might have had a 90-150 second intro 20 years ago, now it's about 40 seconds in the first season, then usually squished to 5-10 in subsequent seasons.
On a DVD or a theater screen you have a captive audience who's already paid to see your product and there's a very little chane of them walking out a minute in, play as many long logos as you want. The rules, or better yet strategy is different.
Edit: forgot to mention that I totally agree that your logo is a part of your marketing and brand identity. Show it, be it, just don't be so in your face with it that it drives people off. We like to put website info at the end of the video with logos and what not, then the ones we sell as downloads we watermark the preview copy (which also is really effective).
