5 x whiteboard animation videos needed with music in background

Hi, I am looking for someone to work with on an ongoing basis for video creation in whiteboard style. an idea of style would be http://www.youtube.com/watch?v=v2U-nyTpHDY except we don't want voice-overs and would want colour and maybe a bit more text as opposed to just images.
You will be provided with a script for the videos as well as all feedback for changes.

I would like 5 videos to be produced (this is the first set out of 15 videos that I need done) in the whiteboard animation style. I would like the videos to have music in the background but it is important for you to ensure that I won't get in trouble for using any music you add to the video as I will be using the video for commercial purposes for my letting agency business.

Some whiteboard videos contain images which use very old/dull colours. If you are using a library source and only have access dullish colours then this won't be appropriate as our company needs the use of vibrant colours in the video. we like the hand that is used in such videos.

This is very likely to be long term ongoing work and we hope to find someone who has a professional and pleasant personality. After the first 5 videos are done, we would use you again for the next 10 as we want the same style/approach used in order to build our look and feel. The 15 videos will cover us for 3 months, thereafter will be looking at a couple more per month.

Please bid stating price for making 5 videos. some videos may be 60 seconds in length, others might be 2mins or 90 seconds.All text will be provided in the format that best suits you, including our logo. We would like to be given the files in common format for uploading to youtube and other video sites such as vimeo. Please ensure your licence allows us to do this.

Please note that we do not have the scripts ready at this moment, but will start working on them once we understand how many words we are allowed per video. thanks and look forward to getting your proposal.
Please note we have a tight budget