As we do videos for many of our web design clients, we have similar issues regarding budget constraints for their lead capture page or homepage.
While site content is undoubtedly continually important for SEO, there's really no better way to convert prospective customers than a well-thought out video. If you're going to undertake a video, I would recommend allocating as many resources as possible (even if it means skirting on some of the web design).
A couple of other ideas than the ones you listed are Stop Motion Animation, Green Screen, or a Whiteboard-based video.
Stop Motion Animation only requires a decent camera and/or photographer. The majority of the effort is on the post-production, but it could be a cheaper tactic to utilize the resources you have. Here are a couple of ideas: http://on.mash.to/brnohE
Green Screen video doesn't necessarily require a professional green screen. If you have a free wall, paint it green and utilize someone's editing experience in post-production. It'd be an excellent way for testimonial videos as well as a potential introductory video.
If I were in your shoes, I'd piggback off SEOMoz and utilize their Whiteboard idea. UPS made it famous, but it's an excellent way to articulate a site's services and/or value, while simultaneously creating a face for the company. It's also super, super cheap to product. Here's an example of a previous SEOMoz Whiteboard Friday: http://mz.cm/J1M912