Rate Limits



I understand that per user / per application twitter REST API rate limit is around 15 requests per rate limit window (of ~15 mins) and search has rate limit of 180 requests per window. Another option is Stream API and rate limit is 1% of total firehouse at a particular moment.

Our requirement is to get as many tweets as possible and streaming API does the job for us(tweets data after the connection is established). But We can not get historical tweet data (like we can read tweet data up to 7 days, 100 tweets per request up to 15 pages by using page parameter-- through REST API and ) by using Stream API.
So, Are there any options by which we can increase (literally unlimited) the rate limit for REST API? Or is there any option where we can buy license related to twitter API? Or any other alternative?

Any suggestions and comments would be of very much help.

Thanks in advance,