Hey Jaret,
I had to do something similar. I had articles stored in a MySQL DB and I wanted to have summaries made of the first 30 words.
Well, I figured there are 2 ways I could do it:
1.) Write a custom function that reads the entire TEXT value and then parses out the first thirty words using my own system of determining what a word is.
2.) Write a custom functiont hat reads in the entire TEXT value and then uses regular expressions to select the first 30 words. Regular expressions made it much easier and faster.
Regarding the word limit for a text field in MySQL. Assuming you are using a recent version of MySQL, the text field can be as large as it needs. It will only run into a problem when the overall table size surpasses the file size limit of your operating system. For windows, thats around 4 gigs, for Solaris its around 60 gig